材料概论复习题01·Thick sheets of flat glass is made by a special float process. 02·Excessive contents of MgO can lead to destructive(毁灭性的) expansion of hardened concrete.03·As the carbon content of steel increases,steel becomes less ductile(柔软的),i.e.,more brittle.04·Magnesium(镁) is hexagonal-close-packed(六方密堆积) in structure.05·In the case of good glass forming materials like SiO2,GeO2 or B2O3, the required rate of cooling of the melts is remarkably low because the maximum crystallization velocities in these materials are themselves very low.06·Dark color of Portland cement is caused by ferrite phase(铁素体),formation of which must be avoided in a white cement.07· In a body-centred cell,there are two particles per elementary cell. 08·Fracture toughness(断裂韧性) is a generic term for measures of resistance to extension of a crack.09·Anisotropy(各向异性) of properties is mainly observed in monocrystalline(单晶) solids.10· Elastomers(橡胶) are the group of polymers that can easily undergo very11· The favorable characteristic of graphite is best lubricity(润滑性). 12·Stiffness(刚度) is expressed by the modulus of elasticity(弹性),also called Young’s modulus.13·When a liquid id=s cooled from a high temperature to its melting temperature,(Tm),it generally solidifies to a crystalline product.14·There are four particles per elementary cell in a face-centred cell. 15·When carbon is mostly in the form of graphite spheroids(球状石墨) and is produced during solidification by inoculating(对金属溶液进行孕育处理) the cast iron with an element such as magnesium while it is still in the ladle(铸勺),the cast iron exhibits very ductile property.16·Titanium is used in high-speed aircraft for its high strength at high temperatures.17·Magnesium is the lightest of all structural metals.18·There are four main aspects materials science and technology: synthesis, manufacturing and processing, composition and structure,properties and performance.19·The silica structure is the basic structure for glass and ceramics. 20·Glasses are coloured with added oxides or halides(卤化物) and made to change their colours or become darker on exposure or light or heat. 21·Traditional fabrication techniques of ceramic contain Hydroplastic22·The term bulk density is used in this instance to refer to a ceramic’s porosity and the fact that most ceramics contain both a crystalline and a noncrystalline phase.翻译1·Glass when newly formed, with a perfect surface, is very strong about five times as strong as steel. This may seem strange, but theoretically glass should be very strong because of the nature of its interatomic bonds. In practice the strength is very much less than the theoretical value. One of the main causes of this loss of strength is the presence of surface defects, such as those caused by chemical corrosion or mechanical abrasion. These flaws can be very small but because glass is rigid they act to concentrate any applied stress over only a few interatomic bonds at the apex of the crack. Under these conditions the strong bonds break and fracture occurs.玻璃刚成型时有着完美的表面，强度是钢的5倍，这看起来或许很奇怪，但由于本身原子间价键的性质，玻璃理论强度应该很大，实际强度却比理论强度低很多。
强度损失的主要原因之一是表面缺陷的存在，例如那些化学腐蚀和机械磨损所造成的缺陷。
这些裂纹可能很小，但因为玻璃是刚性的，所以缺陷会集中所有外加作用力于少数裂纹尖端的原子键上。
在这些条件下，强价键断裂伴随破裂产生。
2·Ceramic compounds can be defined as inorganic compounds made by heating clay or other mineral matter to a high temperature at which they partially melt and bond together.陶瓷复合材料可被定义为通过热加热黏土和其他矿物质达到一个较高的温度使它们部分熔融并粘合在一起的无机化合物。
3· In metal-melting operation,a slag(矿渣) is often necessary to flux(熔化) or combine with impurities(杂质),The slag and impurities then float on the molten metal and are separated and removed after the metal is tapped from(流出) the furnace(熔炉),Limestone(石灰石) is used as a blast furnace(鼓风炉) slag to remove such impurities as sulfur(硫磺) and silica(硅石).在金属熔融操作过程中，需要矿渣来融化和结合杂质。
矿渣和杂质浮于熔融的金属上层，当金属从熔炉中流出后，矿渣和杂质被分离去除。
石灰石就是一种用于鼓风炉中的矿渣，可以用以出去如硫磺、硅石这样的杂质。
4·For a glass-forming oxide A m O n ,there are four rules:the oxyen is linked to two atoms of A, the oxygen coordination around A is 3 or 4,the cation polyhedra share corners,and 3 corners are shared at least.对于一个玻璃形成氧化物A m O n，有四个规则：氧原子和两个A原子相连，围绕A的氧配位数是3或4，阳离子多面体共用顶角，至少3个顶角被共用。
5·The refractive index depends upon the wavelength(光波长) of light, the density(密度), temperature, thermal history, stress, and composition of the glass. （玻璃的）折射率取决于光波长，密度，温度，热处理，压力，玻璃成分6·Ceramic processing can be described simply as consisting of two steps:(1)A cold step,in which the ceramic part is formed or shap ed into a “green”part or preform, and(2) a hot step,in which the green compact is first subjected to heat to dry up any liquid phase formed during the processing and then subject to higher heating, knownas firing, sintering, or densification.陶瓷加工过程可以简单的描述为两个步骤：（1）冷过程，在这个过程中陶瓷部分成型为生坯或预制坯；（2）热处理，在这个过程中生坯首先加热干燥以消除所有液相，然后在更高的温度加热，称为焙烧、烧结和致密化。