The strain rate and prestrain dependences of the flow stress of Ni{sub 3}Ga single crystals
- Univ. of Oxford (United Kingdom). Dept. of Materials
Two Ni{sub 3}Ga single crystals were tested in compression by introducing upward strain rate jumps over the stress strain curve at temperatures ranging from 290 to 840 K. A Cottrell-Stokes-type law is observed below the yield stress peak temperature when the strain rate sensitivity parameter, {beta} = ({delta}{tau}/{delta}ln{dot {epsilon}}) is plotted against the workhardening increment {tau}{sub h}. With increasing temperature, the slopes {beta}/{tau}{sub h} decrease indicating an increase in the activation volume at a given {tau}{sub h}. The microstructure sensitivity of this ordered L{sub 2} alloy is demonstrated by two prestrain experiments. First, a high temperature prestrain reduces the initial values of {beta}, on subsequent deformation at room temperature, compared to that of a virgin specimen at room temperature. Second, a room temperature prestrain weakens the anomaly of the yield stress. The results of the present study are shown to be in broad agreement with earlier results on Ni{sub 3}(Al,Hf)B single crystals.
- OSTI ID:
- 415428
- Journal Information:
- Acta Materialia, Journal Name: Acta Materialia Journal Issue: 11 Vol. 44; ISSN 1359-6454; ISSN ACMAFD
- Country of Publication:
- United States
- Language:
- English
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