Journal Article

Bauschinger Effect and Back Stress in Gradient Cu-Ge Alloy

Jin, Shenbao, Zhou, Hao, Yin, Zhe, Sha, Gang, Yang, Jian, Zhu, Yuntian, Zhu, Xinkun, Gong, Yulan, Hu, Xianzhi

2017

Overview

Using surface mechanical attrition treatment (SMAT), a gradient structure composed of two gradient structure (GS) layers and a coarse grain (CG) layer was generated from a Cu-5.7 wt pct Ge alloy, significantly improving the yield strength of the sample. Unloading–reloading tests showed an unusual Bauschinger effect in these GS samples. The back stresses caused by the accumulated geometrically necessary dislocations (GNDs) on the GS/CG border increased with increasing strain. As found by electron backscatter diffraction (EBSD), the GNDs are mainly distributed in the gradient structured layer, and the density of the GNDs increase with increasing SMAT time. The effect of the back stress increased with increasing SMAT processing time due to the increase in the strain gradient. The pronounced Bauschinger effect in a GS sample can improve the resistance to forward plastic flow and finally contributes to the high strength of GS samples.

• Publisher: Springer US,Springer Nature B.V
• Subject: Alloys / Bauschinger effect / Characterization and Evaluation of Materials / Chemistry and Materials Science / Copper base alloys / Dislocations / Electron backscatter diffraction / Flow resistance / High strength / Materials Science / Metallic Materials / Metallurgy / Microstructure / Nanotechnology / Plastic flow / Recent Progress and New Directions on Mechanical Behavior of Nanostructured Materials: Carl Koch 80th Birthday / Strain / Stress analysis / Structural Materials / Surfaces and Interfaces / Thin Films / Topical Collection: Carl Koch Symposium: Mechanical Behavior of Nanomaterials / Yield strength