课后习题

Introduction to Materials

（材料概论）Questions and Problems （习题）

材料工程学院

1 Introduction to Materials

1.1 With regard to electron configuration,what do all the elements in Group VIIA of the Periodic Table have in common?

1.2 Cite the differences between substance and material.

1.3 Why do we study materials science and engineering?

1.4 Offer an explanation as to why covalently bonded materials are generally less dense than ionically or metallically bonded ones?

1.5 What types of bonding would be expected for each of the following materials:brass,rubber,barium sulfide (BaS),solid xenon,nylon,and aluminum phosphide (AlP)?

1.6 What is the difference between the atomic structure and crystal structure?

1.7 The unit cell for tin has tetragonal symmetry,with a and b lattice parameters of 0.583 and 0.318m,respectively.If its density,atomic weight,and atomic radius are 7.30g/cm3,118.69g/mol,and 0.151nm,respectively,compute the atomic packing factor.

1.8 Cite the primary differences between elastic,anelastic,and plastic deformation behaviour.

1.9 Cite five factors that lead to scatter in measured material properties.

1.10 Besides the mechanical properties and the physico chemical characteristics of materials,which other factors should be considered for the manufacture of an object?

1.11 What material could be used to insulate a furnace heated to 1000℃?Why?

1.12 To which class of building material does wood belong?

1.13 List the materials used in a bicycle.

1.14 Material specification for modern athletic shoes is quite complex.In your opinion what should be the requirement,and why?

1.15 Y ou wish to select the materials needed to carry a current between the components inside an electrical“black box”.What materials would you select?

1.16 Describe some of the key mechanical and physical properties we would consider in selecting a material for an airplane wing.

1.17 In terms of bonding,explain why silicate materials have relatively low densities?

1.18 A three-point bending test is performed on a glass specimen having a rectangular cross section of height d 5mm and width b 10mm; the distance between support points is 45mm.(a) Compute the flexural strength if the load at fracture is 290N.(b) The point of maximum deflection Δy occurs at center of the specimen and is described by:

EI FL y 483

=∆

where E is the modulus of elasticity and I is the cross-section moment of pute Δy at a load of 266N.

2 Metallic Materials

2.1What are the major differences between iron and steel?

2.2List five applications that you encounter every day that use ferrous metals and reason(s).Why these metals were chosen for each application?Can you think of a better material for the application?

2.3List one application,the key structural difference,and the best quality for each of the following cast irons:(a) ductile cast iron,(b) gray cast iron,(c) white iron,(d) malleable iron,(e) wrought iron.

2.4What is the major function of the following in alloy steel:(a) copper,(b) vanadium,(c) chromium,(d) aluminum,(e) lead,(f) nickel,and (g) tungsten?

2.5Describe the major advantages of each of the following stainless steels:(a) martensitic,(b) austenitic,and (c) ferritic.

2.6Name three noble metals and give an application of each.

2.7Explain why aluminum,magnesium,and titanium are expensive when they are so readily available as raw materials.Give a reason for recycling aluminum.

2.8Explain the corrosion resistance mechanism of copper and aluminum.Which metal offers the widest range of processability?

2.9What are (a) brass,(b) bronze,and (c) refractory metals?

2.10(a) What common characteristic do white metals possess?(b) Provide a typical application for each of these metals.(c) Why is lead eliminated from paint,plumbing gasoline,ceramics cookware,and similar uses?

2.11List four properties of magnesium alloys.Cite one example of an application where a magnesium alloy was selected because it possessed one of these properties contained in your list.

2.12Of the nonferrous metals discussed, copper, aluminum, magnesium, nickel, chromium, titanium, gold, silver, platinum, lead, tin, and zinc:

a:What has the highest strength?

b:Which is the lightest in weight?

c:Which is the best electrical conductor?

d:Which is the best thermal conductor?

e:Which offers the best corrosion resistance?

2.13What happens to the properties of hardness,strength,and modulus of elasticity with a decrease in temperature?

2.14Explain what is meant by ductility.

2.15In what ways can fatigue strength be improved?

2.16In what state does a metal conduct best,alloyed or unalloyed?

2.17What is the correlation between metals for electrical and thermal conductivity?

2.18How does the metallic bond work,and what effect does it have on metals?