材料概论

Introduction to Materials（材料概论）Questions and Problems （习题）材料工程学院1 Introduction to Materials1.1 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 You 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:EIFL 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 Materials2.1What 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?3 Ceramic Materials3.1 Based on your knowledge of materials,define “ceramics” in its simplest form.Once you’ve done that,begin constructing a concept map that includes your definition of ceramics and the categories of traditional ceramics and advanced ceramics.3.2 Take one of the properties and see if you can trace this property back to the covalent bonding and/or crystal structure.For example,consider the fact that glass is transparent,but a metal like aluminum is reflective.Try to explain these differences based on the difference in bonding and/or crystal structure.3.3 Sketch the following unit cells:simple cubic,body centered cubic,face centered cubic and hexagonal close packed.Now,look up the following crystal structures and determine which of the structures you just sketched are similar to the following:the rock salt structure,the cesium chloride structure,the fluorite structure,the perovskite structure.3.4 How does biomimetics represent the kind of appeal offered by ceramics for materials selection?What other attributes make ceramics competitive with metals and polymers?3.5 A material’s resistance to the removal of its surface material is known by what terms?3.6 Explain why the machining of fine grained ceramic parts reduces their strength and toughness more than that of large grained ceramic parts.3.7 Surface modification techniques are developed and employed to accomplish what particular goals?3.8 What is the main difference between CVD and CVI processes?3.9 Explain how a material is affected by machining with either dull or improper tools.3.10 Why do ductile materials withstand impact better than brittle materials?3.11 In terms of microstructure,why do crystalline ceramics have different properties from metals that are also crystalline?3.12 Match the ceramic to the application for which it is best suited:(a) Tempered glass(1) Grinding and polishing(b) Fused silica(2) Furnace windows(c) Ferrite(3) Protect metal from oxidation(d) Glaze (porcelain)(4) Computer memory discs(e) 96% silica glass(5) Storm door glazing(f) Diamond(6) Contain hot acids3.13 Consider the characteristics of the general classes of ceramics,plastics,and metals.List the class that is generally superior in the following characteristics;then write down a specific material and value to illustrate its superiority:(a) stiffness,(b) chemical resistance,(c) abundance of raw materials,(d) tensile strength,(e) lowest coefficient of thermal expansion,(f) thermal insulation,(g) hardness,(h) impact strength,(i) flexural strength,(j) density.3.14 In studying the relationship of a finished product in service with its properties and the processes used to produce the product from its basic material(s),one interesting observation is that the final properties desired in a product are usually the cause of the problems that need to be overcome in its processing.An example taken from ceramics deals with the desired properties of high hardness and temperature resistance.These are the very properties that must be overcome in processing the ing metals and/or polymers,cite a general statement that supports the foregoing observation.3.15 When selecting a ceramic material to serve as a heat insulator,would a material with a high density qualify?Discuss your answer.3.16 Ceramic armor,initially developed for the Vietnam War and also used in the Gulf War,was a composite made up of boron carbide (B4C) and fiberglass plus aramid fiber matting.The ceramic has a density of 2.4g/cm3.Is this a low or a high density ceramic?Explain why you think this ceramic was chosen for this application.3.17 Match the correct ceramic to its favorable characteristics.Some will have the same characteristics.(a) Boron nitride(1) Low cost(b) Graphite(2) Machinable(c) Al2O3(3) Best lubricity(d) Glass ceramic(4) Maximum hardness3.18 In terms of their atomic bonding,explain why metals are good conductors and most ceramics are good insulators.3.19 Name some goals of industry and society that caused a push for greater use of ceramics.Describe attributes of ceramics that make them competitive with plastics and metals.Contrast traditional and advanced ceramics.3.20 Use diagrams and explanations to show stress concentrations plus methods to toughen ceramics,including composite matrix ceramics.Define work of fracture and compare work of fracture versus tensile strength in glass,cements,and biomaterials.Make sketches to show methods of improved ceramic structure for greater toughness.4 The Glass Sciences4.1 What is glass briefly? What role does glass play in our ordinary life?4.2 How to produce glass in nature? Please give some examples.4.3 In modern times,what is the main usage for glass?4.4 What are glass fibers? Why can they be used in telecommunication?4.5 How to be coloured during the preparation of glass?4.6 What kind of glasses can be used as lasers?4.7 How to produce optical fibers in industrial technology?4.8 What is oxide or non-oxide glass? Please give some examples about non oxide glass and their usage?4.9 What are the main compositions in oxide glasses are there?4.10 Why does the silica play so important role in glasses?4.11 How many types of main oxide and non-oxide glasses are there?4.12 What is the main usage for chalcogenide glasses?4.13 How to decide whether the glass is amorphous?4.14 What are the temperatures of Tg and Tm? What information can we get from them?4.15 What is the cooling or quenching rate,Q? Why is it important during the formation of glass?4.16 How many roles influence the preparation of glass? What problems should we have to resolve with? Please give some examples about the ways of preparation of glass.4.17 What is the structure models and bonding theories of glass? What is the difference among them?4.18 What is the chemical,physical and optical properties of glass? What application can be done about these properties?4.19 What is the main application for glass? How many special kinds of glasses are there? And how about their applications?4.20 What applications will the glass own in optoelectronic field?5 Cement and Concrete Materials5.1 What is Portland cement?And what is clinker?5.2 How many types of raw materials for producing cement are there and what are they?5.3 What is the purpose of fast cooling of the clinker?5.4 What are chemical and mineralogical compositions of Portland cement?5.5 Please give a description of the properties of C3S,C2S,C3A and C4AF.5.6 Analyze the major factors affecting the rate of hydration.5.7 Cite the order of the rate of hydration of the four mineral phases (C3S,C2S,C3A and C4AF) in cement.5.8 What is concrete?5.9 How many types of raw materials involving in concrete production?And what are their functions,respectively?5.10 Analyze the major factors affecting concrete strength.What is the primary factor in determining the strength?5.11 How does concrete strength change with temperature?Why?5.12 Analyze the importance of aggregate cement paste interface.5.13 What is durability of concrete?And how do you characterize the durability?5.14 Cite the major damages of concrete that influence the durability.5.15 Which method could be taken into account on enhancing the frost resistance of concrete? 5.16 According to your knowledge,how do you achieve a cement based material with very high strength?5.17 What are the advantages of fly ash to the properties of concrete?5.18 How does water reducer take effect in concrete?6 Polymer Materials6. 1 What is polymers?6. 2 What is the most simple and commonly used nomenclature system based on?6. 3 What is the inadequacy of the preceding nomenclature systems?6. 4 Give a brief explanation to the 3 main steps of addition polymerization.6.5 What is the difference between the two ways of termination: combination and disproportionation?6. 6 Why a fundamental knowledge of structure property relations is required?6. 7 Which kind of polymers have high strength and low extensibility ?6. 8 What is the difference between plastics and elastomer?6. 9 How to classify plastics? Please give some examples for their different properties.7 Composite Materials7. 1 What are RP based on?7. 2 How many kinds of composites can be classified on the basis of the form of their structural components?7. 3 What benefits do fillers offer?7. 4 What are the main purposes of surface treatment? And what are the surface changes after the treatment?7. 5 How the silane treatment can improve the dry and wet strength of fiberglass reinforced unsaturated polyester compared with the untreated glass fibers?7. 6 What are the three main groups the most common man made composites can be divided into?7. 7 What are four main direct loads that any material in a structure has to withstand?7. 8 Why is there a very large range of mechanical properties that can be achieved with composite materials?7. 9 How to classify the cement matrix composites? Please describe the main advantages of it.7. 10 How to classify the polymer matrix composites? Please describe the main advantages of it.7. 11 What does the Poisson Effect mean?。