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Effect of Stacking Fault Energy on Cyclic Constitutive Relation Under Nonproportional Loading.

1992; Society of Materials Science; Volume: 41; Issue: 468 Linguagem: Inglês

10.2472/jsms.41.1361

1880-7488

Takamoto Itoh, Masao Sakane, Masateru OHNAMI, Kei Ameyama,

Microstructure and Mechanical Properties of Steels

This paper describes the effect of stacking fault energy (SFE) on cyclic constitutive relation under nonproportional loading. Proportional and nonproportional tension/torsion step-up tests were carried out at room temperature on five materials which have different SFE; they are SUS 304 stainless steel, pure copper, pure nickel, pure aluminum and 6061 aluminum alloy. The material which has small SFE exhibited large additional hardening in nonproportional tests, while the material with large SFE showed no additional hardening due to nonproportional loading. The difference in additional hardening due to SFE was discussed in relation to slip band and cell size. For SUS 304 stainless steel and pure copper, which have small SFE, the interaction between planer slip bands in nonproportional loading was the cause of large additional hardening. On the other hand, for pure nickel, pure aluminum and 6061 aluminum alloy which have large SFE, wavy slips occurred in proportional and nonproportional loadings. Dislocations in large SFE materials can easily change their slip planes so that small or no additional hardening was found in large SFE materials. As SFE decreases, the cell size becomes smaller in nonproportional loading.