In order to improve（）at the interface, the surface of the（）must be treated. A.adhesionB.structureC.matrixD.reinforcement 正确答案：adhesion；reinforcement

（）are offered by metal matrices than those offered by their plastic counterparts. A.higher strengthB.fracture toughnessC.stiffnessD.elastic 正确答案：higher strength；fracture toughness；stiffness

The matrix is the binder material that（）the fibers. A.separatesB.dissolvesC.supportsD.protects 正确答案：separates；supports；protects

The precipitation hardening processes include（）heat treatment and（）heat treatment. 正确答案：solution precipitation

Metal corrosion can be calssified according to the two major processes by which it occurs.One is（）直接氧化corrosion，the second process is（）电化学 corrosion 正确答案：direct oxidation galvanic

The third type of point defect is impurity atom. Impurities can be classified as（）间隙 impurity atom or（）置换impurity atom. 正确答案：interstitial substitutional

The（）steels are highly resistant to corrosion（rusting）in a variety of environments, especially the ambient atmosphere. 正确答案：stainless

（）alloys, in which, iron is the principal constituent, include steels and cast irons. 正确答案：Ferrous

（）metals, by definition, have melting points are above 2000℃, some of them reaching as high as 3426℃. 正确答案：Refractory

Metal processing techniques are normally preceded by refining, alloying and often heat-treating process. A.正确B.错误 正确答案：错误

Ferrous metal has a relatively low density and a comparatively high electrical conductivity. A.正确B.错误 正确答案：错误

A ductile metal becomes harder and stronger as it is elastically deformed. A.正确B.错误 正确答案：错误