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