石墨烯是什么，为什么被称为神奇材料？
What is graphene and why is it called a wonder material?
石墨烯是仅一层碳原子组成的二维蜂窝状薄片，导电导热极快、强度极高又几乎透明。它有望用于更快的芯片、柔性屏和高效电池，但大面积廉价制造仍难。
Graphene is a one-atom-thick honeycomb of carbon with superb conductivity, heat transport and strength yet transparency; it promises faster chips, flexible screens and better batteries, though cheap large-scale making remains hard.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 来源待核验 · Source pending review
来源 · Source
出处备注：著录含书名，但缺版次 / 出版社 / 年份中的一部分，需编辑补全后才能做独立比对。
Geim & Novoselov，《石墨烯的崛起》，《自然·材料》6卷，183–191页（2007）
Geim & Novoselov, 'The rise of graphene,' Nat. Mater. 6, 183–191 (2007)
#材料 #石墨烯 #纳米
钢化玻璃是怎样变得更安全的？
How is tempered glass made safer?
把玻璃加热到接近软化再快速冷却，表面先变硬收缩、内部后冷却，形成表面压应力；这让它更抗冲击，破碎时会裂成圆钝小粒而非尖刀状碎片。
Heating then rapidly cooling glass puts the surface under compression; this makes it impact-resistant and, if it breaks, it shatters into small blunt granules instead of sharp shards.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 3 条独立证据
来源 · Source
Callister，《材料科学与工程导论》（第10版）
Callister, 'Materials Science and Engineering: An Introduction' (10th ed.)
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-1-119-45520-2 (Global Ed.) / 978-1-119-45391-8 · 核验依据 2 ISBN 9781292247137 · 核验依据 3 ISBN 9781641950565 (2019)
#材料 #钢化玻璃 #安全
钢筋混凝土里的钢筋为什么要放在'受拉'的一边？
Why is rebar placed on the tension side of concrete?
混凝土抗压不抗拉，钢筋抗拉，二者粘结互补，截面受弯才高效。
Concrete resists compression but not tension; steel takes the tension, so the bonded pair bends efficiently.
难度 专业 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-10-03
来源 · Source
ACI 318；Hibbeler《材料力学》
ACI 318; Hibbeler, Mechanics of Materials
独立核验依据 · Independent verification: 核验依据 1 ISBN 9781292247137
#工程材料 #材料科学
为什么大多数金属冷却凝固时会收缩，而水结冰反而膨胀？
Why do most metals shrink on cooling but water expands when freezing?
金属原子在固态晶格中排列比液态更紧密，所以凝固时体积缩小。水的冰晶因氢键形成开放的六方结构，固态反而比液态占据更大空间，因此结冰膨胀、密度变小。
Metal atoms pack more tightly in the solid lattice than in the liquid, so freezing shrinks volume. Water's ice crystals form an open hexagonal structure via hydrogen bonds, occupying more space solid than liquid, so it expands and gets less dense.
难度 专业 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 3 条独立证据
来源 · Source
Callister，《材料科学与工程导论》（第10版）
Callister, 'Materials Science and Engineering: An Introduction' (10th ed.)
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-1-119-45520-2 (Global Ed.) / 978-1-119-45391-8 · 核验依据 2 ISBN 9781292247137 · 核验依据 3 ISBN 9781641950565 (2019)
#凝固 #密度 #氢键
钢里为什么要加锰、铬等元素？
Why add manganese, chromium and such to steel?
锰脱氧并强化，铬形成致密氧化膜防锈（不锈钢）；微量元素调硬度韧性。
Manganese deoxidizes and strengthens; chromium forms a protective film against rust (stainless); traces tune hardness and toughness.
难度 专业 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 3 条独立证据
来源 · Source
ASM International《金属手册》第1卷；Callister《材料科学与工程导论》
ASM International, 'ASM Handbook' Vol. 1; Callister, 'Materials Science and Engineering: An Introduction'
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-1-119-45520-2 (Global Ed.) / 978-1-119-45391-8 · 核验依据 2 ISBN 9781292247137 · 核验依据 3 ISBN 9781641950565 (2019)
#工程材料 #材料科学
不锈钢为什么不像普通钢那样生锈？
Why doesn't stainless steel rust like ordinary steel?
铬对氧的亲和力高于铁，钢见空气便自发生成一层几个纳米厚、连续致密的氧化铬钝化膜，隔断氧和水、挡住离子穿膜，腐蚀速率因此下降几个数量级；划伤后只要有氧，铬重新氧化便把膜补上。普通钢的铁锈疏松含水、比基体大又易剥落，腐蚀层层向内推进。不锈钢不是不腐蚀而是靠钝化：缺氧缝隙、氯离子或酸性环境会破膜起点蚀，铬含量得先过一道门槛。
Chromium's affinity for oxygen beats iron's, so on contact with air the steel grows a continuous, dense chromium-oxide passive film only a few nanometers thick, shutting out oxygen and water and blocking ions across it, which cuts the corrosion rate by orders of magnitude; where it is scratched, chromium re-oxidizes and reseals the film as long as oxygen is present. Rust on ordinary steel is porous hydrated iron oxide, bulkier than the metal beneath, poorly bonded and flaking, so corrosion presses inward layer by layer. Stainless is not immune but passive: oxygen-starved crevices, chloride or acid service break the film and start pitting, and chromium content must first pass a threshold.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 3 条独立证据
来源 · Source
Callister《材料科学》；ASTM A240（不锈钢）
Callister, Materials Science; ASTM A240 (stainless steel)
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-1-119-45520-2 (Global Ed.) / 978-1-119-45391-8 · 核验依据 2 ISBN 9781292247137 · 核验依据 3 ISBN 9781641950565 (2019)
#工程材料 #材料科学
'玻璃是缓慢流动的液体'这种说法错在哪？
Why is 'glass is a slow-flowing liquid' wrong?
玻璃是过冷固体（非晶态），室温下并不流动；老窗上薄下厚是当年擀制工艺所致。
Glass is an amorphous solid, not flowing at room temperature; old window thickness differences came from old rolling methods.
难度 专业 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 3 条独立证据
来源 · Source
Callister《材料科学与工程》；ACI 318《混凝土结构设计规范》；ASTM 材料标准
Callister, Materials Science and Engineering; ACI 318, Building Code Requirements for Structural Concrete; ASTM standards
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-1-119-45520-2 (Global Ed.) / 978-1-119-45391-8 · 核验依据 2 ISBN 9781292247137 · 核验依据 3 ISBN 9781641950565 (2019)
#工程材料 #材料科学
碳纤维为什么又轻又特别结实？
Why is carbon fiber both very light and especially strong?
碳纤维是极细的碳晶体沿纤维方向高度排列，碳原子键很强且材料密度低；沿纤维方向抗拉强度高，常用树脂粘成层板，在飞机和赛车中替代金属减重。
Carbon fiber is tiny carbon crystals aligned along the filament with strong atomic bonds and low density; its tensile strength along the fiber is high, and resin-bonded layers replace metal to save weight in aircraft and race cars.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 3 条独立证据
来源 · Source
Callister，《材料科学与工程导论》（第10版）
Callister, 'Materials Science and Engineering: An Introduction' (10th ed.)
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-1-119-45520-2 (Global Ed.) / 978-1-119-45391-8 · 核验依据 2 ISBN 9781292247137 · 核验依据 3 ISBN 9781641950565 (2019)
#材料 #碳纤维 #复合材料
奥氏体不锈钢明明很耐蚀，为什么在含氯离子的热环境里会突然开裂？
Austenitic stainless steel resists corrosion well, so why does it crack suddenly in hot chloride environments?
这是氯离子引起的应力腐蚀开裂：拉应力（包括焊接残余应力）、敏感材料与氯离子介质同时存在时，氯离子在局部击穿钝化膜，裂尖金属持续溶解而侧壁重新钝化，裂纹便以极窄的分支形态穿晶扩展。宏观上几乎没有失重和塑性变形，外观看不出腐蚀，却可能在远低于屈服强度的应力下穿透管壁，典型场景是保温层下的 304/316 管道和泳池上方的不锈钢吊挂件。对策包括改用高钼、双相或超级奥氏体钢，焊后消除残余应力，控制保温层浸水与氯含量，并避免不锈钢长期停留在 50–150 ℃ 的含氯冷凝环境。
This is chloride stress-corrosion cracking, which needs tensile stress (including welding residual stress), a susceptible alloy and chloride ions together: chlorides locally break down the passive film, the crack tip keeps dissolving while flanks repassivate, and a very narrow branching transgranular crack advances. There is almost no weight loss or visible deformation, yet a wall can be penetrated at stresses far below yield, the classic cases being 304/316 piping under wet insulation and stainless suspension parts above swimming pools. Countermeasures are higher-molybdenum, duplex or super-austenitic grades, post-weld stress relief, keeping insulation dry and low in chloride, and avoiding prolonged service in chloride condensate around 50–150 °C.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-10-04
来源 · Source
《ASM Handbook, Vol. 13A: Corrosion — Fundamentals, Testing, and Protection》
'ASM Handbook, Vol. 13A: Corrosion — Fundamentals, Testing, and Protection'
独立核验依据 · Independent verification: 核验依据 1 ISBN 9781947192898 (2021)
#应力腐蚀开裂 #氯离子 #不锈钢
在合金设计中，固溶强化和析出强化分别靠什么机制提高强度？
In alloy design, how do solid-solution and precipitation strengthening raise strength?
固溶强化靠把异类原子溶入基体晶格，引起晶格畸变从而阻碍位错运动。析出强化则让细小第二相颗粒从过饱和固溶体中析出，位错必须切过或绕过这些颗粒，需要额外应力，因此显著提高强度。
Solid-solution strengthening dissolves alien atoms into the lattice, distorting it and hindering dislocation motion. Precipitation strengthening lets fine second-phase particles precipitate from a supersaturated solution; dislocations must cut through or bypass them, requiring extra stress and raising strength.
难度 专业 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 3 条独立证据
来源 · Source
Callister，《材料科学与工程导论》（第10版）
Callister, 'Materials Science and Engineering: An Introduction' (10th ed.)
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-1-119-45520-2 (Global Ed.) / 978-1-119-45391-8 · 核验依据 2 ISBN 9781292247137 · 核验依据 3 ISBN 9781641950565 (2019)
#合金 #位错 #强化
泡沫金属（如泡沫铝）有什么用？
What are metal foams (like aluminum foam) for?
轻、吸能、隔音隔热，常用于缓冲吸能结构和轻量化部件。
They are light, energy-absorbing and insulating, used in crash structures and lightweight parts.
难度 专业 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 3 条独立证据
来源 · Source
Hibbeler《材料力学》；Callister《材料科学与工程》；Gibson & Ashby《多孔固体》
Hibbeler, Mechanics of Materials; Callister, Materials Science and Engineering; Gibson & Ashby, Cellular Solids
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-1-119-45520-2 (Global Ed.) / 978-1-119-45391-8 · 核验依据 2 ISBN 9781292247137 · 核验依据 3 ISBN 9781641950565 (2019)
#工程材料 #材料科学
混凝土浇好后为什么要'养护'洒水？
Why cure concrete with water after pouring?
水化反应需要水和时间，保湿防裂、才能达到设计强度，早干会粉化。
Hydration needs water and time; keeping it moist prevents cracks and reaches design strength—drying early makes it crumble.
难度 专业 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-11-02
来源 · Source
ACI 308（混凝土养护规范）
ACI 308, Standard Practice for Curing Concrete
独立核验依据 · Independent verification: 核验依据 1 OPENLIBRARY 标识 /works/OL12055546W：Standard practice for
#工程材料 #材料科学
预应力混凝土为什么能跨更大的距离？
Why can prestressed concrete span farther?
提前加压抵消使用荷载带来的拉应力，延迟开裂、提高刚度与跨径。
Pre-compression cancels the tension from live loads, delaying cracks and raising stiffness and span.
难度 专业 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-11-03
来源 · Source
Lin & Burns《预应力混凝土设计》；ACI 318
Lin & Burns, Design of Prestressed Concrete; ACI 318
独立核验依据 · Independent verification: 核验依据 1 OPENLIBRARY 标识 /works/OL21252250W：Design of Prestressed
#工程材料 #材料科学
金属增材制造为什么要充惰性气体、打印完还要热处理去应力？
Why is metal additive manufacturing done in inert gas, with heat treatment after printing?
这是金属增材制造中的粉末床熔融工艺：激光或电子束按切片数据逐层扫描金属粉末，每层熔化凝固后铺新粉再熔，层层堆积成零件。激光工艺必须在氩气或氮气等惰性气氛中进行，防止高温熔池被氧化——氧化会让材料变脆并产生气孔；电子束工艺则在真空室中完成，真空同样隔绝了氧。但逐层快速熔凝带来两大工程难题：一是残余应力大，热应力会让薄壁件翘曲开裂，所以需要支撑结构和打印后的去应力热处理；二是凝固组织方向性强（柱状晶），力学性能存在各向异性，常需热等静压消除内部孔隙。它擅长制造复杂内腔和拓扑优化结构，但成本和速度仍高于传统加工。
This is the powder-bed fusion process of metal additive manufacturing: a laser or electron beam scans each sliced layer over metal powder, melting and solidifying it, then fresh powder is spread and melted again, building the part up layer by layer. Laser-based processes run in an inert atmosphere (argon or nitrogen) to keep the molten pool from oxidizing — oxidation embrittles the material and creates pores; electron-beam melting instead works in a vacuum chamber, which excludes oxygen just as effectively. Rapid layer-wise melting brings two hard problems: large residual stress, which warps and cracks thin features (hence supports and stress-relief heat treatment), and strongly directional columnar solidification giving anisotropic mechanical properties, usually remedied by hot isostatic pressing to close internal pores. It excels at complex internal channels and topology-optimized parts, but remains slower and costlier than conventional machining.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-11-04
来源 · Source
DebRoy、Wei、Zuback 与 Mukherjee,《Additive manufacturing of metallic components – Process, structure and properties》,Progress in Materials Science,2018 (DOI: 10.1016/j.pmatsci.2017.10.001)
DebRoy, Wei, Zuback & Mukherjee, 'Additive manufacturing of metallic components – Process, structure and properties', Progress in Materials Science, 2018, DOI: 10.1016/j.pmatsci.2017.10.001
独立核验依据 · Independent verification: 核验依据 1 Crossref DOI 10.1016/j.pmatsci.2017.10.001
#增材制造 #残余应力 #粉末床熔融
为什么往纯金属里掺一点点其他元素，性能就大不一样？
Why does adding a small amount of another element drastically change a metal's properties?
纯金属的原子排列规则，位错很容易滑移，所以纯铝、纯铁又软又弱。加入合金元素后，原子尺寸差异引起晶格畸变，阻碍位错运动，这叫固溶强化；还能析出细小的第二相颗粒把位错"钉住"，即沉淀强化。钢就是铁中加入约0.8%的碳，再通过控制冷却让碳化物析出，强度成倍提升；而奥氏体到马氏体的相变则是钢热处理强化的核心机制。
In pure metals atoms line up regularly and dislocations glide easily, so pure aluminum or iron is soft and weak. Adding alloying elements distorts the lattice with their different atomic sizes, blocking dislocation motion — solid-solution strengthening — and tiny second-phase particles can also pin dislocations, which is precipitation hardening. Steel is iron with about 0.8% carbon; controlling the cooling makes carbides precipitate and multiplies strength. The austenite-to-martensite phase transformation is the heart of steel heat treatment.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 来源待核验 · Source pending review
来源 · Source
出处备注：著录仅给书名，无版次与年份；同一书名常对应多个版次，不臆测具体版本。
《自然》杂志（材料科学）
Nature (materials science)
#合金 #位错 #相变
为什么马路护栏和电线杆要镀上一层锌？
Why are highway guardrails and utility poles coated with zinc?
锌保护钢铁有两层机制：物理上，锌层把钢与水、氧气隔开，阻挡腐蚀介质；更重要的是锌比铁活泼，是"牺牲阳极"——即使表面划破露出钢，锌也会优先腐蚀，通过电偶作用让钢免锈。热浸镀锌把钢件浸入熔融锌液，形成与钢材冶金结合的锌铁合金层，寿命可达数十年。造船、桥梁、风电塔筒等长期暴露的钢构件都大量采用，这是最经济的长效防腐手段之一。
Zinc protects steel in two ways: physically the coating seals the steel from water and oxygen, and more importantly zinc is more active than iron, so it acts as a sacrificial anode — even where the coating is scratched, the zinc corrodes first and protects the steel galvanically. Hot-dip galvanizing immerses parts in molten zinc, forming a metallurgically bonded zinc-iron alloy layer that can last decades. Ships, bridges, and wind-tower legs in harsh environments rely on it as one of the cheapest long-term corrosion defenses.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
David Macaulay,《The Way Things Work》,Houghton Mifflin,1988;中译《万物运转的秘密》
D. Macaulay, The Way Things Work, Houghton Mifflin, 1988; Chinese ed.
独立核验依据 · Independent verification: 核验依据 2 OPENLIBRARY 标识 /works/OL15130328W：The Way Things Work（按标
#镀锌 #牺牲阳极 #防腐
气凝胶为什么轻得像空气却能隔热，它的纳米多孔结构起什么作用？
Why is aerogel air-light yet insulating, and what does its nanoporous structure do?
气凝胶约99%是空气，骨架是纳米级网络，固相传热路径被切得极碎，气体又被困在小于自由程的孔里难以对流。于是对流、传导、辐射都被压制，成为顶级隔热材料。
Aerogel is about 99% air in a nanoscale network; the solid conduction path is shattered and gas is trapped in pores smaller than its mean free path, suppressing convection. Conduction, convection and radiation are all throttled, making it a top insulator.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-11-03
来源 · Source
Aegerter & Leventis 编，《气凝胶手册》（2011）
Aegerter & Leventis (eds.), 'Aerogels Handbook' (2011)
独立核验依据 · Independent verification: 核验依据 1 OPENLIBRARY 标识 /works/OL16940698W：Aerogels Handbook（首版 2
#气凝胶 #纳米多孔 #隔热
高熵合金为什么用五种以上元素“乱混”反而可能比传统合金更强韧？
Why can high-entropy alloys, mixing five or more elements 'randomly', be stronger and tougher than traditional alloys?
多主元造成严重晶格畸变、缓慢扩散和“鸡尾酒效应”，既阻碍位错运动提高强度，又靠混乱结构延缓裂纹。传统合金靠一两种主元，反而少了这种协同强化。
Many principal elements cause severe lattice distortion, sluggish diffusion and a 'cocktail effect', blocking dislocations for strength while the disordered structure slows cracks. Traditional alloys with one or two main elements miss this synergy.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-11-03
来源 · Source
Yeh 等，《多主元纳米结构高熵合金》，《先进工程材料》6卷，299–303页（2004）
Yeh et al., 'Nanostructured high-entropy alloys with multiple principal elements,' Adv. Eng. Mater. 6, 299–303 (2004)
独立核验依据 · Independent verification: 核验依据 1 CROSSREF 标识 10.1002/adem.200300567：Nanostructured High‐E
#高熵合金 #晶格畸变 #协同强化
什么是回火，淬火后的钢为什么要再加热一次？
What is tempering and why is quenched steel reheated?
淬火让钢变得极硬却很脆、内应力大。回火是把钢重新加热到较低温度再缓冷，使部分马氏体分解、析出碳化物，从而降低脆性、提高韧性，牺牲一点硬度换取可用性。
Quenching makes steel very hard but brittle with high internal stress. Tempering reheats it to a lower temperature then cools slowly, letting some martensite decompose and carbides precipitate, trading a little hardness for much-needed toughness.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 3 条独立证据
来源 · Source
Callister，《材料科学与工程导论》（第10版）
Callister, 'Materials Science and Engineering: An Introduction' (10th ed.)
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-1-119-45520-2 (Global Ed.) / 978-1-119-45391-8 · 核验依据 2 ISBN 9781292247137 · 核验依据 3 ISBN 9781641950565 (2019)
#回火 #淬火 #韧性
为什么碳纤维材料又轻又强，却那么贵？
Why is carbon fiber so light and strong yet so expensive?
碳纤维单丝直径只有5到10微米，内部碳原子沿轴向整齐排列成石墨片层，轴向抗拉强度是钢材的数倍，密度却只有钢的四分之一。但单根纤维像线一样不能承压，必须用树脂把成千上万根纤维粘成复合材料层合板，纤维方向还可以按受力方向铺设设计。贵就贵在原料要高温碳化、工艺链长且能耗高，成型还需要热压罐，所以主要用于航空航天、高端汽车和体育器材。
Carbon fiber filaments are only 5-10 micrometers across, with carbon atoms aligned along the axis in graphite sheets, giving several times steel's tensile strength at a quarter of its density. But a single filament is like a thread and takes no compression, so thousands of fibers must be bonded in resin to form composite laminates, with the fiber direction engineered to match the load path. It is expensive because the raw material must be carbonized at high temperature in a long, energy-hungry process, and curing needs autoclaves — which is why it is reserved for aerospace, premium cars, and sports equipment.
难度 进阶 · 适合 大众
CC BY 4.0 · 来源待核验 · Source pending review
来源 · Source
出处备注：著录仅给书名，无版次与年份；同一书名常对应多个版次，不臆测具体版本。
《自然》杂志（材料科学）
Nature (materials science)
#碳纤维 #复合材料 #比强度
什么是金属疲劳，为什么反复弯折铁丝最终会断？
What is metal fatigue and why does bending wire back and forth eventually break it?
疲劳是材料在低于强度的反复应力下逐渐产生微裂纹并扩展的现象。每次弯折都在应力集中处损伤一点，裂纹长大到临界尺寸后突然断裂，即使总受力远小于静强度。
Fatigue is the gradual growth of microcracks under repeated stress below the material's strength. Each bend adds damage at stress concentrators; once a crack reaches critical size it snaps, even though loads were far below static strength.
难度 进阶 · 适合 小学高段(9-12)
CC BY 4.0 · 已核验 · Verified 2026-11-03
来源 · Source
Dieter，《机械冶金学》（第5版）
Dieter, 'Mechanical Metallurgy' (5th ed.)
独立核验依据 · Independent verification: 核验依据 1 CROSSREF 标识 10.5962/bhl.title.35895：Mechanical metallurg
#疲劳 #裂纹 #循环载荷
什么是相变增韧，氧化锆陶瓷如何利用它抵抗裂纹扩展？
What is transformation toughening and how does zirconia ceramic use it against cracks?
氧化锆在受力时会从四方相转变为单斜相，体积略有膨胀，在裂纹尖端产生压应力把裂纹夹紧，消耗扩展能量。这种相变增韧让脆性陶瓷也能承受一定冲击而不易碎裂。
Zirconia transforms from tetragonal to monoclinic phase under stress, expanding slightly and squeezing the crack tip with compressive stress that clamps it and absorbs energy. This transformation toughening lets brittle ceramic survive impacts.
难度 进阶 · 适合 小学低段(6-8)
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 3 条独立证据
来源 · Source
Callister，《材料科学与工程导论》（第10版）
Callister, 'Materials Science and Engineering: An Introduction' (10th ed.)
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-1-119-45520-2 (Global Ed.) / 978-1-119-45391-8 · 核验依据 2 ISBN 9781292247137 · 核验依据 3 ISBN 9781641950565 (2019)
#氧化锆 #相变 #增韧
焊接接头出问题为什么常常不在焊缝本身，而在旁边的热影响区？
Why do welded joints often fail beside the weld, in the heat-affected zone, rather than in the weld metal?
热影响区没有熔化，却经历了接近熔点的快速加热与冷却，近缝处晶粒严重粗化，冷却速度高的碳钢还会生成硬而脆的马氏体，韧性明显低于母材。焊缝金属可以通过填充材料成分和工艺主动控制组织，而热影响区的组织完全由热循环决定，再叠加焊接残余应力与氢的富集，就容易出现冷裂纹、氢致裂纹或脆化。控制办法是限定碳当量、预热并控制层间温度以降低冷却速率、限制热输入避免晶粒过分粗化，必要时焊后热处理消除残余应力与硬化组织。
The heat-affected zone never melts but is heated near the melting point and cooled quickly, so grains coarsen severely next to the fusion line and carbon steels with fast cooling form hard, brittle martensite with toughness well below the base metal. Weld metal can be given matching or over-matched filler chemistry and controlled solidification, whereas HAZ microstructure is dictated purely by the thermal cycle, and combined with residual stress and hydrogen pickup it becomes the site of cold cracking, hydrogen-induced cracking or embrittlement. Remedies include limiting carbon equivalent, preheat and interpass temperature control to slow cooling, capping heat input to avoid excessive grain growth, and post-weld heat treatment to relieve stress and temper hard zones.
难度 进阶 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-10-04
来源 · Source
Kou，《Welding Metallurgy》（第2版，Wiley，2003）
Kou, 'Welding Metallurgy' (2nd ed., Wiley, 2003)
独立核验依据 · Independent verification: 核验依据 1 ISBN 9780471460930 (2003)
#热影响区 #焊接冶金 #冷裂纹
为什么混凝土要加钢筋？
Why add steel to concrete?
混凝土抗压怕拉，钢筋补上抗拉能力。
Concrete resists compression but not tension; steel adds that.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-11-03
来源 · Source
Neville，《混凝土的性能》（第5版）
Neville, 'Properties of Concrete' (5th ed.)
独立核验依据 · Independent verification: 核验依据 1 OPENLIBRARY 标识 /works/OL11330446W：Properties of concrete
#钢筋混凝土 #抗拉 #抗压
为什么工程陶瓷的强度要用韦布尔分布来描述，而金属常给一个确定的屈服强度？
Why is the strength of engineering ceramics described with a Weibull distribution while metals get a single yield strength?
陶瓷几乎没有塑性变形能力，裂纹尖端的应力无法通过屈服被削平，构件强度由体内或表面最严重的那个缺陷决定，是典型的最弱链环问题。缺陷尺寸随机分布，同批试样的断裂强度离散很大，需要用韦布尔分布的特征强度与形状参数 m 来表征，m 越小说明缺陷分散越严重。由此还产生尺寸效应：体积越大越可能含有大缺陷，平均强度反而下降，所以陶瓷按允许失效概率取许用应力，并靠热压致密化和精细研磨减小缺陷，而不是去『提高屈服强度』。
Ceramics have almost no plasticity to blunt crack-tip stresses, so component strength is set by the single most severe flaw present, a classic weakest-link problem. Flaw sizes are randomly distributed, so measured fracture strengths scatter widely and are characterized by a Weibull characteristic strength plus a modulus m, where a small m means highly variable flaws. That also produces a size effect: larger volumes more likely contain a large flaw, so mean strength falls with size, and ceramic design assigns allowable stress from an accepted failure probability while hot pressing and fine polishing shrink flaws, rather than trying to raise a yield point.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 2 条独立证据
来源 · Source
Callister 与 Rethwisch，《Materials Science and Engineering: An Introduction》（第10版）
Callister & Rethwisch, 'Materials Science and Engineering: An Introduction' (10th ed.)
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-1-119-45520-2 (Global Ed.) / 978-1-119-45391-8
#工程陶瓷 #韦布尔分布 #缺陷统计
碳纤维为什么又轻又硬，却常常很脆？
Why is carbon fiber light and stiff yet often brittle?
碳纤维沿纤维方向由规整的石墨微晶构成，键强很高所以比强度大、刚性好。但它主要靠纤维本身承力，缺乏塑性变形能力，受横向冲击或弯折时容易分层或脆断。
Carbon fiber's aligned graphite crystallites give very high specific strength and stiffness. But it relies on the fibers themselves and lacks ductility, so transverse impact or bending causes delamination or brittle breakage.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 3 条独立证据
来源 · Source
Callister，《材料科学与工程导论》（第10版）
Callister, 'Materials Science and Engineering: An Introduction' (10th ed.)
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-1-119-45520-2 (Global Ed.) / 978-1-119-45391-8 · 核验依据 2 ISBN 9781292247137 · 核验依据 3 ISBN 9781641950565 (2019)
#碳纤维 #复合材料 #脆性
超材料是什么，为什么能做出“隐身”或负折射这种自然界没有的特性？
What are metamaterials, and how can they achieve nature-defying traits like invisibility or negative refraction?
超材料不是靠成分而是靠人工周期性微结构来操控电磁波、声波等，等效参数可突破自然材料范围。设计成让波绕行或反向折射，就能做隐身斗篷或超透镜。
Metamaterials rely on artificial periodic microstructures rather than composition to steer electromagnetic or acoustic waves, reaching parameters beyond natural materials. Engineered to bend waves around objects or refract negatively, they enable cloaks and superlenses.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-11-02
来源 · Source
Smith、Pendry & Wiltshire，《超材料与负折射率》，《科学》305卷，788–792页（2004）
Smith, Pendry & Wiltshire, 'Metamaterials and Negative Refractive Index,' Science 305, 788–792 (2004)
独立核验依据 · Independent verification: 核验依据 1 EUROPEPMC 标识 15297655：Metamaterials and negative refract
#超材料 #周期性结构 #负折射
普通钢和不锈钢有什么区别？
What is the difference between ordinary steel and stainless steel?
不锈钢在铁和碳之外加了铬等元素，铬在表面形成致密的氧化膜，阻止水和氧继续侵蚀，所以不容易生锈；普通钢缺少这层保护易生锈。
Stainless steel adds chromium, which forms a dense oxide film on the surface that blocks water and oxygen, so it resists rust; ordinary steel lacks this shield and corrodes easily.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 3 条独立证据
来源 · Source
Callister，《材料科学与工程导论》（第10版）
Callister, 'Materials Science and Engineering: An Introduction' (10th ed.)
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-1-119-45520-2 (Global Ed.) / 978-1-119-45391-8 · 核验依据 2 ISBN 9781292247137 · 核验依据 3 ISBN 9781641950565 (2019)
#材料 #不锈钢 #耐腐蚀
同样是给织物上色，为什么涤纶只能靠分散染料在约130℃高温下染色，而不能像棉那样用活性染料与纤维形成共价键？
When coloring fabrics, why must polyester rely on disperse dyes applied near 130 degrees C instead of anchoring reactive dyes to the fiber with covalent bonds the way cotton does?
直答：染色路径取决于纤维的化学结构与物理形态，涤纶大分子排列紧密、结晶度高，链上缺少能与染料反应的活性基团，染料只能以溶解扩散方式进入无定形区。机理：分散染料几乎不溶于水，靠分散剂以微粒悬浮于染浴；温度超过纤维玻璃化温度后链段运动打开瞬时空隙，染料扩散速率才足以进入纤维并驻留于疏水内部；棉纤维富含羟基，活性染料在碱催化下与之共价结合，常压即可完成，两条路线截然不同。
How a fiber takes color is fixed by its chemistry and physical texture: polyester chains pack tightly into a highly crystalline structure with no reactive sites, leaving dissolution-and-diffusion into amorphous regions as the only route in. Disperse dyes barely dissolve in water and ride through the bath as particles held by dispersing agents; only above the glass transition, where segmental motion opens transient gaps, is diffusion fast enough for dye to enter and lodge in the hydrophobic interior. Cotton, rich in hydroxyl groups, bonds reactive dyes covalently under alkaline catalysis at ordinary pressure — two utterly different routes.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-11-02
来源 · Source
王菊生主编《染整工艺原理》，纺织工业出版社，1982年 ; 另见: A.D. Broadbent, Basic Principles of Textile Coloration, Society of Dyers and Colourists, 2001
A.D. Broadbent, Basic Principles of Textile Coloration, Society of Dyers and Colourists, 2001 ; see also: 王菊生主编《染整工艺原理》，纺织工业出版社，1982年
独立核验依据 · Independent verification: 核验依据 1 OPENLIBRARY 标识 /works/OL9611110W：Basic Principles of Tex
#分散染料 #涤纶染色 #玻璃化温度
相图计算（CALPHAD）是什么，它怎么在不做实验的情况下预测合金会不会析出有害相？
What is CALPHAD, and how can it predict without experiments whether an alloy will precipitate harmful phases?
CALPHAD 用热力学数据库和模型计算多组元体系在各温度的成分平衡，画出相图。输入合金配方就能预告哪些温度下会析出脆性相或偏析，指导成分设计。
CALPHAD uses thermodynamic databases and models to compute equilibrium compositions of multicomponent systems at each temperature, drawing phase diagrams. Feed an alloy recipe and it forecasts brittle precipitates or segregation, guiding design.
难度 进阶 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-11-04
来源 · Source
Saunders & Miodownik,《CALPHAD: Calculation of Phase Diagrams - A Comprehensive Guide》,Pergamon Materials Series,1998 (DOI: 10.1016/s1470-1804(98)x8001-6)
Saunders & Miodownik, 'CALPHAD: Calculation of Phase Diagrams - A Comprehensive Guide', Pergamon Materials Series, 1998, DOI: 10.1016/s1470-1804(98)x8001-6
独立核验依据 · Independent verification: 核验依据 1 Crossref DOI 10.1016/s1470-1804(98)x8001-6
#CALPHAD #相图 #热力学
自修复材料为什么被划伤后能“自己长好”，它里面藏了什么机关？
Why can self-healing materials 'grow back' after a scratch—what mechanism is hidden inside?
一类藏有微胶囊，破裂时流出修复剂在裂缝处固化；另一类用可逆化学键，受热或光照就能重新接上断键。像皮肤结痂一样，把损伤自动补上。
One type hides microcapsules that release healing agent to solidify in the crack; another uses reversible bonds that re-link under heat or light. Like skin scabbing, damage is mended automatically.
难度 入门 · 适合 大众
CC BY 4.0 · 来源待核验 · Source pending review
来源 · Source
出处备注：著录含书名，但缺版次 / 出版社 / 年份中的一部分，需编辑补全后才能做独立比对。
White 等，《聚合物复合材料的自主愈合》，《自然》409卷，794–797页（2001）
White et al., 'Autonomous healing of polymer composites,' Nature 409, 794–797 (2001)
#自修复 #微胶囊 #可逆键
为什么不锈钢不容易生锈？
Why doesn't stainless steel rust easily?
不锈钢含铬，铬在空气中与氧反应在表面形成一层极薄且致密的氧化铬保护膜，把内部金属和水分、氧气隔开，从而阻止继续腐蚀。
Stainless steel contains chromium, which forms a thin, dense chromium-oxide film in air that seals the metal from water and oxygen, stopping further corrosion.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 3 条独立证据
来源 · Source
Callister，《材料科学与工程导论》（第10版）
Callister, 'Materials Science and Engineering: An Introduction' (10th ed.)
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-1-119-45520-2 (Global Ed.) / 978-1-119-45391-8 · 核验依据 2 ISBN 9781292247137 · 核验依据 3 ISBN 9781641950565 (2019)
#不锈钢 #铬 #氧化膜
同一块木头，顺着纹路很难拉断，横着掰却容易开，这是为什么？
Why is a piece of wood very hard to pull apart along the grain yet easy to split across it?
木材由沿树干方向排列的管状细胞组成，细胞壁里的纤维素微纤丝也大致顺着这个方向，顺纹受拉时力沿着强度很高的纤维传递。横纹方向靠的是细胞之间较弱的木质素粘结和细胞壁的横向支撑，抗拉强度往往只有顺纹的几十分之一，裂缝顺着细胞界面很容易延伸。木工因此让承重梁的纹路顺着跨度方向，胶合板则把奇数层薄板交错九十度叠放，用互相垂直的纹理弥补横纹的弱点。
Wood is built from tube-like cells aligned with the trunk, and the cellulose microfibrils in their walls run roughly the same way, so pulling along the grain loads very strong fibres directly. Across the grain the load must pass through weaker lignin bonding between cells, so tensile strength perpendicular to the grain is often a small fraction of the parallel value and cracks run easily along cell boundaries. Carpenters therefore align beam grain with the span, and plywood glues an odd number of veneers at ninety degrees to each other so crossed grain compensates for the weak direction.
难度 入门 · 适合 小学低段(6-8)
CC BY 4.0 · 已核验 · Verified 2026-11-03
来源 · Source
美国农业部林务局，《Wood Handbook: Wood as an Engineering Material》（FPL-GTR-282）
USDA Forest Service, 'Wood Handbook: Wood as an Engineering Material' (FPL-GTR-282)
独立核验依据 · Independent verification: 核验依据 1 OPENLIBRARY 标识 /works/OL34277664W：Wood Handbook - Wood A
#木材各向异性 #顺纹强度 #胶合板
混凝土是什么，为什么到处都在用它？
What is concrete and why is it used almost everywhere?
混凝土是水泥、砂、石子和水拌在一起硬化成的石头状材料，便宜、可塑形、抗压好，能浇成各种形状，所以广泛用于房屋、道路和桥梁。
Concrete is cement, sand, gravel and water mixed into a stone-like mass; it is cheap, moldable and strong in compression, so it is poured into countless shapes for buildings, roads and bridges.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-11-03
来源 · Source
Neville，《混凝土的性能》（第5版）
Neville, 'Properties of Concrete' (5th ed.)
独立核验依据 · Independent verification: 核验依据 1 OPENLIBRARY 标识 /works/OL11330446W：Properties of concrete
#材料 #混凝土 #水泥
铁为什么会生锈，怎么防止它生锈？
Why does iron rust and how can we stop it?
铁和水、氧气一起发生化学反应生成疏松的铁锈，会越烂越大。刷漆、镀锌或涂油能把铁和空气水分隔开，就能防锈。
Iron reacts with water and oxygen to form flaky rust that keeps spreading; painting, galvanizing with zinc, or oiling blocks contact with air and moisture to prevent it.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 3 条独立证据
来源 · Source
Callister，《材料科学与工程导论》（第10版）
Callister, 'Materials Science and Engineering: An Introduction' (10th ed.)
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-1-119-45520-2 (Global Ed.) / 978-1-119-45391-8 · 核验依据 2 ISBN 9781292247137 · 核验依据 3 ISBN 9781641950565 (2019)
#材料 #生锈 #防腐
为什么防弹玻璃能挡住子弹，它和普通玻璃差别在哪？
Why can bulletproof glass stop bullets, and how is it different from ordinary glass?
防弹玻璃是把多层硬玻璃和柔软的塑料夹层粘在一起，子弹打来时硬层把力分散、软层把能量吸收并兜住碎片。普通玻璃一撞就碎成尖片，根本挡不住。
Bulletproof glass bonds many hard glass layers with soft plastic interlayers; the hard layers spread the force and the soft layers absorb energy and catch shards. Ordinary glass just shatters into sharp pieces and cannot stop a bullet.
难度 入门 · 适合 幼儿(3-6)
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 3 条独立证据
来源 · Source
Callister，《材料科学与工程导论》（第10版）
Callister, 'Materials Science and Engineering: An Introduction' (10th ed.)
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-1-119-45520-2 (Global Ed.) / 978-1-119-45391-8 · 核验依据 2 ISBN 9781292247137 · 核验依据 3 ISBN 9781641950565 (2019)
#防弹玻璃 #夹层 #能量吸收
玻璃是怎么用沙子做出来的？
How is glass made from sand?
主要原料是二氧化硅砂子，加热到很高温度熔化成液态，再快速冷却不让它结晶，就得到了透明、硬而脆的玻璃。
The main ingredient is silica sand, heated until it melts, then cooled quickly so it does not crystallize, giving a transparent, hard, brittle solid we call glass.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 3 条独立证据
来源 · Source
Callister，《材料科学与工程导论》（第10版）
Callister, 'Materials Science and Engineering: An Introduction' (10th ed.)
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-1-119-45520-2 (Global Ed.) / 978-1-119-45391-8 · 核验依据 2 ISBN 9781292247137 · 核验依据 3 ISBN 9781641950565 (2019)
#材料 #玻璃 #二氧化硅
同样是用短纤维纺纱，为什么环锭纱的强力普遍高于转杯纱？
Why do ring-spun yarns come out consistently stronger than rotor-spun yarns made from the same staple fibers?
直答：环锭纱内纤维沿近似圆锥螺旋线排列，伸直平行度高，受拉时绝大多数纤维共同承载；转杯纱结构分层且含大量缠绕纤维，强力先天受限。机理：环锭加捻依靠钢丝圈张力使纤维内外转移，两端握持、张力连续，拉断前多数纤维先后断裂；转杯纱纤维在凝聚槽内呈单侧握持状态，外层缠包纤维仅起捆扎作用、芯层捻度不足，拉伸时滑移纤维占比高，成纱强力通常低一到两成。
Ring-spun fibers lie along near-conical helixes, straightened and parallel, so under tension nearly all of them carry load together; rotor yarns are layered structures laced with wrapper fibers that cap strength from the outset. Ring twisting uses traveler tension to migrate fibers inward and outward with both ends gripped under continuous tension, so most fibers must break before the yarn fails. Rotor fibers are gripped from one side only in the grooved channel: outer wrappers merely lash the bundle, the core carries little twist, and slipping fibers dominate under load, leaving strength some ten to twenty percent lower.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-11-02
来源 · Source
郁崇文主编《纺纱学》，中国纺织出版社，2014年 ; 另见: C.A. Lawrence, Fundamentals of Spun Yarn Technology, CRC Press, 2003
C.A. Lawrence, Fundamentals of Spun Yarn Technology, CRC Press, 2003 ; see also: 郁崇文主编《纺纱学》，中国纺织出版社，2014年
独立核验依据 · Independent verification: 核验依据 1 OPENLIBRARY 标识 /works/OL5959475W：Fundamentals of spun ya
#环锭纺纱 #转杯纺纱 #纤维滑移
玻璃是怎么做出来的，为什么是透明的？
How is glass made and why is it transparent?
把沙子里的二氧化硅高温熔化成液体再快速冷却，不结晶就成玻璃。它的电子结构没有能吸收可见光的能级间隙，所以可见光直接穿过去，看起来透明。
Silica from sand is melted at high temperature and cooled quickly without crystallizing into glass. Its electronic structure has no energy gap to absorb visible light, so light passes through and it looks transparent.
难度 入门 · 适合 幼儿(3-6)
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 3 条独立证据
来源 · Source
Callister，《材料科学与工程导论》（第10版）
Callister, 'Materials Science and Engineering: An Introduction' (10th ed.)
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-1-119-45520-2 (Global Ed.) / 978-1-119-45391-8 · 核验依据 2 ISBN 9781292247137 · 核验依据 3 ISBN 9781641950565 (2019)
#玻璃 #二氧化硅 #透明