重庆大学：《金属材料的力学行为 mechanical behavior of metallic materials》PPT教学课件（1/2，彭晓东）

Mechanical Behavior of Metallic Materials(1) PENG Xiaodong Ph.D. Professor School of materials science and Engineering Chongqing University Chongqing 400044 P.R. China

Mechanical Behavior of Metallic Materials(1) PENG Xiaodong Ph.D., Professor School of Materials Science and Engineering Chongqing University Chongqing 400044 P.R. China

Mechanical Behavior of metallic Materials 主要参考书 Deformation and Editions Fracture Mechanics of Engineering materials 2013 1996 1989 1983 1976 Richard W. Hertzberg· achard P vinc· jason L Hertzberg Fifth Edition Contact information Email:pxd@cqu.edu.cn yanyang@cqu.edu.cn CHONGOING UNIVENTTY

Mechanical Behavior of Metallic Materials 主要参考书 Editions 2013 1996 1989 1983 1976 Contact information Email：pxd@cqu.edu.cn yanyang@cqu.edu.cn

Mechanical Behavior of metallic Materials Introduction Discuss macroscopic and microscopic aspects of the mechanical behaviors of metallic materials: Concern with metallurgical principles including crystal structure. materials science and fracture mechanics mechanical metallurgy; The crystal physics approach: the role of dislocations in controlling mechanical properties; e The classical metallurgical approach: the relationship between microstructure and properties; The fracture mechanics approach the relationship between material toughness, design stress, and allowable flaw size ③大季

Mechanical Behavior of Metallic Materials Introduction ⚫ Discuss macroscopic and microscopic aspects of the mechanical behaviors of metallic materials; ⚫ Concern with metallurgical principles including crystal structure, materials science and fracture mechanics---- mechanical metallurgy; ⚫ The crystal physics approach: the role of dislocations in controlling mechanical properties; ⚫ The classical metallurgical approach: the relationship between microstructure and properties; ⚫ The fracture mechanics approach: the relationship between material toughness, design stress, and allowable flaw size

Mechanical Behavior of Metallic materials Force distributions in structures ③大季

Mechanical Behavior of Metallic Materials Force distributions in structures

l Behavior of metallic materials Nanocrystalline Ni3Al alloy Machined 650c 725 1 mm ③產大

Mechanical Behavior of Metallic Materials

Mechanical Behavior of metallic Materials Section 1: Deformation of metals Stress and strain ● Definition: engineering eng true stress. true stress. engineering true strain: 8 In eng true strain. ③大季

Mechanical Behavior of Metallic Materials Stress and Strain ⚫ Definition: Section 1: Deformation of Metals engineering stress: 0 eng P A  = engineering strain: 0 0 f eng l l l  − = true stress: true i P A  = true strain: 0 ln f true l l  =

Mechanical Behavior of metallic Materials The fundamental distinction concerning the two definitions for stress and strain is recognition of the relationshil between the gage length and diameter changes associated with plastic deformation. Since plastic deformation is a constant volume process, any extension of the original gage length would produce a corresponding contraction of the gage diameter. TTotal true strain: =1n生+ln true CHONGQING UNIVENTTY

Mechanical Behavior of Metallic Materials The fundamental distinction concerning the two definitions for stress and strain is recognition of the relationship between the gage length and diameter changes associated with plastic deformation. Since plastic deformation is a constant volume process, any extension of the original gage length would produce a corresponding contraction of the gage diameter. Total true strain: 1 2 2 0 1 0 true ln ln ln l l l l l l  = + =

Mechanical Behavior of metallic Materials Tensile Test e Information that can be obtained from any complete tensile test record includes the material,s elastic properties, the character and extent of plastic deformation, yield and tensile strength, and toughness. Corrected FIGURE 1.5 Type ll stress-strain behavior revealing elastic behavior followed by a region of homogeneous plastic deformation. Data plotted on basis of engineering true stress-strain definitions ③大季

Mechanical Behavior of Metallic Materials ⚫ Information that can be obtained from any complete tensile test record includes the material’s elastic properties, the character and extent of plastic deformation, yield and tensile strength, and toughness. Tensile Test

Mechanical Behavior of metallic Materials Table 1. 8 Round Tension Test Specimen Dimensions L Diameter (D) Gage Length (L) mm (in.) mm (in.) 12.5 (0.5) 50 (2.0 8.75 (0.345) 35 (1.375) 6.25 (0.25) 25 (1.0) 4.0 (0.16) 16 (0.63) 2.50 (0.1) 10 0.394) ③大

Mechanical Behavior of Metallic Materials

Mechanical Behavior of metallic Materials 250 AJ50 alloy 200 150 100 50 0.00 0.05 0,10 0.15 0.20 0.25 Stress-strain curves obtained for various temperatures. (1)Room temperature, (2)50C,(3)100C,(4)150C,(5)200C,(6)250C,(7)300C ③千大

Mechanical Behavior of Metallic Materials Stress–strain curves obtained for various temperatures. (1) Room temperature, (2) 50 ◦C, (3) 100 ◦C, (4) 150 ◦C, (5) 200 ◦C, (6) 250 ◦C, (7) 300 ◦C. AJ50 alloy