Grain boundary sliding and non-constancy strain during stress relaxation of pure Mg

被引:11
作者
Varma, Anand [1 ]
Gokhale, Aditya [1 ]
Krishnaswamy, Hariharan [2 ]
Banerjee, Dilip K. [3 ]
Jain, Jayant [1 ]
机构
[1] Indian Inst Technol, Dept Mat Sci & Engn, Delhi 110016, India
[2] Indian Inst Technol, Dept Mech Engn, Madras 600036, Tamil Nadu, India
[3] NIST, Mat Measurement Lab, Gaithersburg, MD 20899 USA
来源
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING | 2021年 / 817卷
关键词
Stress relaxation; Magnesium; Grain boundary sliding; ROOM-TEMPERATURE; QUANTITATIVE-EVALUATION; DUCTILITY IMPROVEMENT; MAGNESIUM ALLOYS; NONBASAL SLIP; CREEP; DEFORMATION; DISLOCATIONS; MECHANISMS; BEHAVIOR;
D O I
10.1016/j.msea.2021.141349
中图分类号
TB3 [工程材料学];
学科分类号
0805 ; 080502 ;
摘要
Stress relaxation during plastic deformation has been reported to improve ductility of metallic materials. In this study, the stress relaxation behaviour in pure magnesium is investigated during interrupted uniaxial tensile tests. During intermittent stopping of the machine for relaxation studies, the total strain is expected to remain constant. However, an anomalous non-constancy in total strain is observed in the present work. The total strain increases with relaxation time. Additional in-situ tensile tests indicate that the non-constant total strain is restricted only in the gauge area of the specimen, indicating a likely shear dominated deformation such as grain boundary sliding (GBS) responsible for the anomalous behaviour. The role of GBS during relaxation is studied using the deformation induced evolution of surface inhomogeneity. Determinations of surface profiling step heights at grain boundaries and inclination of grains were used to quantify the effect of GBS. The estimated activation volume of 4.35 b3 further confirms the role of slip induced GBS on the deformation. A new stress relaxation model accommodating GBS is proposed and is found to fit the experimental data accurately.
引用
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页数:11
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