FundamentalsofMaterialsScienceandEngineering英文习题及思考题及答案.pdf

往链点点通 www.WL 往链点点通 www.WL 往链点点通共享资源，了解更多请登录 www.WL 材料科学与工程基础英文习题及思考题及答案 第二章第二章 习题习题和思考题和思考题 Questions and Problems 2.6 Allowed values for the quantum numbers ofelectrons are as follows: The relationships between n and the shell designationsare noted in Table 2.1. Relative tothe subshells, l 0 corresponds to an s subshell l 1 corresponds to a p subshell l 2 corresponds to a d subshell l 3 corresponds to an f subshell For the K shell, the four quantum numbersfor each of the two electrons in the 1s state, inthe order of nlmlms , are 100(1/2 ) and 100(-1/2 ).Write the four quantum numbers for allof the electrons intheLandMshells, and notewhich correspond to the s, p, and d subshells. 2.7 Give the electron configurations for the followingions: Fe2+, Fe3+, Cu+, Ba2+, Br-, andS2-. 2.17 (a) Briefly cite the main differences betweenionic, covalent, and metallic bonding. (b) State the Pauli exclusion principle. 2.18 Offer an explanation as to why covalently bonded materials are generally less dense than ionically or metallically bonded ones. 2.19 Compute the percents ionic character of the interatomic bonds for the following compounds: TiO2 , ZnTe, CsCl, InSb, and MgCl2 . 2.21 Using Table 2.2, determine the number of covalent bonds that are possible for atoms of the following elements: germanium, phosphorus, selenium, and chlorine. 2.24 On the basis of the hydrogen bond, explain the anomalous behavior of water when it freezes. That is, why is there volume expansion upon solidification? 3.1 What is the difference between atomic structure and crystal structure? 3.2 What is the difference between a crystal structure and a crystal system? 3.4 Show for the body-centered cubic crystal structure that the unit cell edge length a and the atomic radius R are related through a =4R/3. 3.6 Show that the atomic packing factor for BCC is 0.68. . 3.27* Show that the minimum cation-to-anion radius ratio for a coordination 往链点点通 www.WL 往链点点通 www.WL number of 6 is 0.414. Hint: Use the NaCl crystal structure (Figure 3.5), and assume that anions and cations are just touching along cube edges and across face diagonals. 3.48 Draw an orthorhombic unit cell, and within that cell a 121 direction and a (210) plane. 3.50 Here are unit cells for two hypothetical metals: (a) What are the indices for the directions indicated by the two vectors in sketch (a)? (b) What are the indices for the two planes drawn in sketch (b)? 3.51* Within a cubic unit cell, sketch the following directions: . 3.53 Determine the indices for the directions shown in the following cubic unit cell: 往链点点通 www.WL 往链点点通 www.WL 3.57 Determine the Miller indices for the planes shown in the following unit cell: 3.58 Determine the Miller indices for the planes shown in the following unit cell: 3.61* Sketch within a cubic unit cell the following planes: 3.62 Sketch the atomic packing of (a) the (100) plane for the FCC crystal structure, and (b) the (111) plane for the BCC crystal structure (similar to Figures 3.24b and 3.25b). 3.77 Explain why the properties of polycrystalline materials are most often isotropic. 5.1 Calculate the fraction of atom sites that are vacant for lead at its melting temperature of 327_C. Assume an energy for vacancy formation of 0.55 eV/atom. 5.7 If cupric oxide (CuO) is exposed to reducing atmospheres at elevated temperatures, some of the Cu2_ ions will become Cu_. (a) Under these conditions, name one crystalline defect that you would expect to form in order to maintain charge neutrality. (b) How many Cu_ ions are required for the creation of each defect? 5.8 Below, atomic radius, crystal structure, electronegativity, and the most common valence are tabulated, for several elements; for those that are nonmetals, only atomic radii are indicated. 往链点点通 www.WL 往链点点通 www.WL Which of these elements would you expect to form the following with copper: (a) A substitutional solid solution having complete solubility? (b) A substitutional solid solution of incomplete solubility? (c) An interstitial solid solution? 5.9 For both FCC and BCC crystal structures, there are two different types of interstitial sites. In each case, one site is larger than the other, which site is normally occupied by impurity atoms. For FCC, this larger one is located at the center of each edge of the unit cell; it is termed an octahedral interstitial site. On the other hand, with BCC the larger site type is found at 0, _, _ positionsthat is, lying on _100_ faces, and situated midway between two unit cell edges on this face and one-quarter of the distance between the other two unit cell edges; it is termed a tetrahedral interstitial site. For both FCC and BCC crystal structures, compute the radius r of an impurity atom that will just fit into one of these sites in terms of the atomic radius R of the host atom. 5.10 (a) Suppose that Li2O is added as an impurity to CaO. If the Li_ substitutes for Ca2_, what kind of vacancies would you expect to form? How many of these vacancies are created for every Li_ added? (b) Suppose that CaCl2 is added as an impurity to CaO. If the Cl_ substitutes for O2_, what kind of vacancies would you expect to form? How many of the vacancies are created for every Cl_ added? 5.28 Copper and platinum both have the FCC crystal structure and Cu forms a substitutional solid solution for concentrations up to approximately 6 wt% Cu at room temperature. Compute the unit cell edge length for a 95 wt% Pt-5 wt% Cu alloy. 5.29 Cite the relative Burgers vectordislocation line orientations for edge, screw, and mixed dislocations. 6.1 Briefly explain the difference between selfdiffusion and interdiffusion. 6.3 (a) Compare interstitial and vacancy atomic mechanisms for diffusion. (b) Cite two reasons why interstitial diffusion is normally more rapid than vacancy diffusion. 6.4 Briefly explain the concept of steady state as it applies to diffusion. 6.5 (a) Briefly explain the concept of a driving force. (b) What is the driving force for steadystate diffusion? 往链点点通 www.WL 往链点点通 www.WL 6.6 Compute the number of kilograms of hydrogen that pass per hour through a 5-mm thick sheet of palladium having an area of 0.20 m2 at 500. Assume a diffusion coefficient of 1.010- 8 m2/s, that the concentrations at the high- and low-pressure sides of the plate are 2.4 and 0.6 kg of hydrogen per cubic meter of palladium, and that steady-state conditions have been attained. 6.7 A sheet of steel 1.5 mm thick has nitrogen atmospheres on both sides at 1200 and is permitted to achieve a steady-state diffusion condition. The diffusion coefficient for nitrogen in steel at this temperature is 610-11 m2/s, and the diffusion flux is found to be 1.210- 7 kg/m2-s. Also, it is known that the concentration of nitrogen in the steel at the high-pressure surface is 4 kg/m3. How far into the sheet from this high-pressure side will the concentration be 2.0 kg/m3? Assume a linear concentration profile. 6.24. Carbon is allowed to diffuse through a steel plate 15 mm thick. The concentrations of carbon at the two faces are 0.65 and 0.30 kg C/m3 Fe, which are maintained constant. If the preexponential and activation energy are 6.2 _ 10_7 m2/s and 80,000 J/mol, respectively, compute the temperature at which the diffusion flux is 1.43 _ 10_9 kg/m2-s. 6.25 The steady-state diffusion flux through a metal plate is 5.4_10_10 kg/m2-s at a temperature of 727_C (1000 K) and when the concentration gradient is _350 kg/m4. Calculate the diffusion flux at 1027_C (1300 K) for the same concentration gradient and assuming an activation energy for diffusion of 125,000 J/mol. 10.2 What thermodynamic condition must be met for a state of equilibrium to exist? 10.4 What is the difference between the states of phase equilibrium and metastability? 10.5 Cite the phases that are present and the phase compositions for the following alloys: (a) 90 wt% Zn10 wt% Cu at 400 (b) 75 wt% Sn25wt%Pb at 175 (c) 55 wt% Ag45 wt% Cu at 900 (d) 30 wt% Pb70 wt% Mg at 425 (e) 2.12 kg Zn and 1.88 kg Cu at 500 (f ) 37 lbm Pb and 6.5 lbm Mg at 400 (g) 8.2 mol Ni and 4.3 mol Cu at 1250. (h) 4.5 mol Sn and 0.45 mol Pb at 200 10.6 For an alloy of composition 74 wt% Zn26 wt% Cu, cite the phases present and their compositions at the following temperatures: 850, 750, 680, 600, and 500. 10.7 Determine the relative amounts (in terms of mass fractions) of the phases for the alloys and temperatures given in Problem 10.5. 10.9 Determine the relative amounts (in terms of volume fractions) of the phases for the alloys and temperatures given in Problem 10.5a, b, and c. Below are given the approximate densities of the various metals at the alloy temperatures: 10.18 Is it possible to have a coppersilver alloy that, at equilibrium, consists of a _ phase of composition 92 wt% Ag8 往链点点通 www.WL 往链点点通 www.WL wt% Cu, and also a liquid phase of composition 76 wt% Ag24 wt% Cu? If so, what will be the approximate temperature of the alloy? If this is not possible, explain why. 10.20 A coppernickel alloy of composition 70 wt% Ni30 wt% Cu is slowly heated from a temperature of 1300_C . (a) At what temperature does the first liquid phase form? (b) What is the composition of this liquid phase? (c) At what temperature does complete melting of the alloy occur? (d) What is the composition of the last solid remaining prior to complete melting? 10.28 .Is it possible to have a coppersilver alloy of composition 50 wt% Ag50 wt% Cu, which, at equilibrium, consists of _ and _ phases having mass fractionsW_ _ 0.60 and W_ _ 0.40? If so, what will be the approximate temperature of the alloy? If such an alloy is not possible, explain why. 10.30 At 700_C , what is the maximum solubility (a) of Cu in Ag? (b) Of Ag in Cu? 第三章第三章 习题和思考题习题和思考题 3.3 If the atomic radius of aluminum is 0.143nm, calculate the volume of its unit cell in cubic meters. 3.8 Iron has a BCC crystal structure, an atomic radius of 0.124 nm, and an atomic weight of 55.85 g/mol. Compute and compare its density with the experimental value found inside the front cover. 3.9 Calculate the radius of an iridium atom given that Ir has an FCC crystal structure, a density of 22.4 g/cm3, and an atomic weight of 192.2 g/mol. 3.13 Using atomic weight, crystal structure, and atomic radius data tabulated inside the front cover, compute the theoretical densities of lead, chromium, copper, and cobalt, and then compare these values with the measured densities listed in this same table. The c/a ratio for cobalt is 1.623. 3.15 Below are listed the atomic weight, density, and atomic radius for three hypothetical alloys. For each determine whether its crystal structure is FCC, BCC, or simple cubic and then justify your determination. A simple cubic unit cell is shown in Figure 3.40. 3.21 This is a unit cell for a hypothetical metal: (a) To which crystal system does this unit cell belong? (b) What would this crystal structure be called? (c) Calculate the density of the material, given that its atomic weight is 141 g/mol. 往链点点通 www.WL 往链点点通 www.WL 3.25 For a ceramic compound, what are the two characteristics of the component ions that determine the crystal structure? 3.29 On the basis of ionic charge and ionic radii, predict the crystal structures for the following materials: (a) CsI, (b) NiO, (c) KI, and (d) NiS. Justify your selections. 3.35 Magnesium oxide has the rock salt crystal structure and a density of 3.58 g/cm3. (a) Determine the unit cell edge length. (b) How does this result compare with the edge length as determined from the radii in Table 3.4, assuming that the Mg2_ and O2_ ions just touch each other along the edges? 3.36 Compute the theoretical density of diamond given that the CUC distance and bond angle are 0.154 nm and 109.5 , respectively. How does this value compare with the measured density? 3.38 Cadmium sulfide (CdS) has a cubic unit cell, and from x-ray diffraction data it is known that the cell edge length is 0.582 nm. If the measured density is 4.82 g/cm 3 , how many Cd 2+ and S 2 ions are there per unit cell? 3.41 A hypothetical AX type of ceramic material is known to have a density of 2.65 g/cm 3 and a unit cell of cubic symmetry with a cell edge length of 0.43 nm. The atomic weights of the A and X elements are 86.6 and 40.3 g/mol, respectively. On the basis of this information, which of the following crystal structures is (are) possible for this material: rock salt, cesium chloride, or zinc blende? Justify your choice(s). 3.42 The unit cell for Mg Fe2O3 (MgO-Fe2O3) has cubic symmetry with a unit cell edge length of 0.836 nm. If the density of this material is 4.52 g/cm 3 , compute its atomic packing factor. For this computation, you will need to use ionic radii listed in Table 3.4. 3.44 Compute the atomic packing factor for the diamond cubic crystal structure (Figure 3.16). Assume that bonding atoms touch one another, that the angle between adjacent bonds is 109.5 , and that each atom internal to the unit cell is positioned a/4 of the distance away from the two nearest cell faces (a is the unit cell edge length). 3.45 Compute the atomic packing factor for cesium chloride using the ionic radii in Table 3.4 and assuming that the ions touch along the cube diagonals. 3.46 In terms of bonding, explain why silicate materials have relatively low densities. 3.47 Determine the angle between covalent bonds in an SiO44 tetrahedron. 3.63 For each of the following crystal structures, represent the indicated plane in the manner of Figures 3.24 and 3.25, showing both anions and cations: (a) (100) 往链点点通 www.WL 往链点点通 www.WL plane for the rock salt crystal structure, (b) (110) plane for the cesium chloride crystal structure, (c) (111) plane for the zinc blende crystal structure, and (d) (110) plane for the perovskite crystal structure. 3.66 The zinc blende crystal structure is one that may be generated from close-packed planes of anions. (a) Will the stacking sequence for this structure be FCC or HCP? Why? (b) Will cations fill tetrahedral or octahedral positions? Why? (c) What fraction of the positions will be occupied? 3.81* The metal iridium has an FCC crystal structure. If the angle of diffraction for the (220) set of planes occurs at 69.22 (first-order reflection) when monochromatic x-radiation having a wavelength of 0.1542 nm is used, compute (a) the interplanar spacing for this set of planes, and (b) the atomic radius for an iridium atom. 4.10 What is the difference between configuration and conformation in relation to polymer chains? vinyl chloride). 4.22 (a) Determine the ratio of butadiene to styrene mers in a copolymer having a weight-average molecular weight of 350,000 g/mol and weight-average degree of polymerization of 4425. (b) Which type(s) of copolymer(s) will this copolymer be, considering the following possibilities: random, alternating, graft, and block? Why? 4.23 Crosslinked copolymers consisting of 60 wt% ethylene and 40 wt% propylene may have elastic properties similar to those for natural rubber. For a copolymer of this composition, determine the fraction of both mer types. 4.25 (a) Compare the crystalline state in metals and polymers. (b) Compare the noncrystalline state as it applies to polymers and ceramic glasses. 4.26 Explain briefly why the tendency of a polymer to crystallize decreases with increasing molecular weight. 4.27* For each of the following pairs of polymers, do the following: (1) state whether or not it is possible to determine if one polymer is more likely to crystallize than the other; (2) if it is possible, note which is the more likely and then cite reason(s) for your choice; and (3) if it is not possible to decide, then state why. (a) Linear and syndiotactic polyvinyl chloride; linear and isotactic polystyrene. (b) Network phenol-formaldehyde; linear and heavily crosslinked cis-isoprene. (c) Linear polyethylene; lightly branched isotactic polypropylene. (d) Alternating poly(styrene-ethylene) copolymer; random poly(vinylchloride-tetrafluoroethylene) copolymer. 4.28 Compute the density of totally crystalline polyethylene. The orthorhombic unit cell for polyethylene is shown in Figure 4.10; also, the equivalent of two ethylene mer units is contained within each unit cell. 5.11 What point defects are possible for MgO as an impurity in Al2O3? How many Mg 2+ ions must be added to form each of these defects? 5.13 What is the composition, in weight percent, of an alloy that consists of 6 at% Pb and 94 at% Sn? 5.14 Calculate the composition, in weight per-cent, of an alloy that contains 218.0 kg titanium, 14.6 kg of aluminum, and 9.7 kg of vanadium. 5.23 Gold forms a substitutional solid solution with silver. Compute the number of gold atoms per cubic centimeter for a silver-gold alloy that contains 10 wt% Au and 90 wt% Ag. The densities of pure gold and silver are 19.32 and 10.49 g/cm 往链点点通 www.WL 往链点点通 www.WL 3 , respectively. 8.53 In terms of molecular structure, explain why phenol-formaldehyde (Bakelite) will not be an elastomer. 10.50 Compute the mass fractions of ferrite and cementite in pearlite. assuming that pressure is held constant. 10.52 (a) What is the distinction between hypoeutectoid and hypereutectoid steels? (b) In a hypoeutectoid steel, both eutectoid and proeutectoid ferrite exist. Explain the difference between them. What will be the carbon concentration in each? 10.56 Consider 1.0 kg of austenite containing 1.15 wt% C, cooled to below 727_C (a) What is the proeutectoid phase? (b) How many kilograms each of total ferrite and cementite form? (c) How many kilograms each of pearlite and the proeutectoid phase form? (d) Schematically sketch and label the resulting microstructure. 10.60 The mass fractions of total ferrite and total cementite in an ironcarbon alloy are 0.88 and 0.12, respectively. Is this a hypoeutectoid or hypereutectoid alloy? Why? 10.64 Is it possible to have an ironcarbon a