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1、Chapter 1The Structure of Metals1;.Metal and Non-metal Use in AutomobilesFigure I.1 Some of the metallic and nonmetallic materials used in a typical automobile2;.Engineering Materials of Part IFigure I.2 An outline of the engineering materials described in Part I.3;.Behavior and Manufacturing Proper

2、ties of Part IFigure I.3 An outline of the behavior and the manufacturing properties of materials described in Part I.4;.Chapter 1: The Structure of MetalsFigure 1.1 An outline of the topics described in Chapter 1.5;.Crystal Structure of MetalsBody-centered cubic (BCC) - alpha iron, chromium, molybd

3、enum, tantalum, tungsten, and vanadium.Face-centered cubic (FCC) - gamma iron, aluminum, copper, nickel, lead, silver, gold and platinum.Hexagonal close-packed - beryllium, cadmium, cobalt, magnesium, alpha titanium, zinc and zirconium.Common crystal structures for metals:6;.Body-centered Cubic Crys

4、tal StructureFigure 1.2 The body-centered cubic (bcc) crystal structure: (a) hard-ball model; (b) unit cell; and (c) single crystal with many unit cells7;.Face-centered Cubic Crystal StructureFigure 1.3 The face-centered cubic (fcc) crystal structure: (a) hard-ball model; (b) unit cell; and (c) sing

5、le crystal with many unit cells8;.Hexagonal Close-packed Crystal StructureFigure 1.4 The hexagonal close-packed (hcp) crystal structure: (a) unit cell; and (b) single crystal with many unit cells.9;.Permanent DeformationFigure 1.5 Permanent deformation (also called plastic deformation) of a single c

6、rystal subjected to a shear stress: (a) structure before deformation; and (b) permanent deformation by slip. The b/a ratio influences the magnitude of the shear stress required to cause slip.10;.Permanent Deformation and Twinning in CrystalFigure 1.6 (a) Permanent deformation of a single crystal und

7、er a tensile load. Note that the slip planes tend to align themselves in the direction of the pulling force. This behavior can be simulated using a deck of cards with a rubber band around them. (b) Twinning in a single crystal in tension.11;.Slip Lines and Slip Bands in CrystalFigure 1.7 Schematic i

8、llustration of slip lines and slip bands in a single crystal (grain) subjected to a shear stress. A slip band consists of a number of slip planes. The crystal at the center of the upper illustration is an individual grain surrounded by several other grains12;.Defects in a Single-Crystal LatticeFigur

9、e 1.8 Schematic illustration of types of defects in a single-crystal lattice: self-interstitial, vacancy, interstitial, and substitutional13;.Dislocations in CrystalsFigure 1.9 Types of dislocations in a single crystal: (a) edge dislocation; and (b) screw dislocation14;.Edge Dislocation MovementFigu

10、re 1.10 Movement of an edge dislocation across the crystal lattice under a shear stress. Dislocations help explain why the actual strength of metals is much lower than that predicted by theory.15;.Solidification of Molten MetalFigure 1.11 Schematic illustration of the stages during solidification of

11、 molten metal; each small square represents a unit cell. (a) Nucleation of crystals at random sites in the molten metal; note that the crystallographic orientation of each site is different. (b) and (c) Growth of crystals as solidification continues. (d) Solidified metal, showing individual grains a

12、nd grain boundaries; note the different angles at which neighboring grains meet each other. 16;.Grain Sizeswhere N = Grains per square inch at 100 x magnificationn = ASTM grain size numberN = 2n-1ASTM Grain Size:17;.Plastic Deformation of Idealized GrainsFigure 1.12 Plastic deformation of idealized

13、(equiaxed) grains in a specimen subjected to compression (such as occurs in the forging or rolling of metals): (a) before deformation; and (b) after deformation. Note the alignment of grain boundaries along a horizontal direction; this effect is known as preferred orientation.18;.Cracks in Sheet Met

14、alFigure 1.13 (a) Schematic illustration of a crack in sheet metal that has been subjected to bulging (caused by, for example, pushing a steel ball against the sheet). Note the orientation of the crack with respect to the rolling direction of the sheet; this sheet is anisotropic. (b) Aluminum sheet with a crack (vertical dark line at the center) developed in a bulge test; the rolling direction of the sheet was vertical. Source: Courtesy of J.S. Kallend, Illinois Institute of Technology19;.Recovery, Recrystallization, and Grain Growth EffectsFigure 1.14 Schematic illustration of the effe

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