The strain rate and prestrain dependences of the flow stress of Ni3Ga single crystals

✍ Scribed by S.S. Ezz

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 716 KB
• Volume: 44
• Category: Article
• ISSN: 1359-6454
• DOI: 10.1016/1359-6454(96)00071-7

✦ Synopsis

Two NilGa 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, /I = (&/61nl) is plotted against the workhardening increment oh. With increasing temperature, the slopes p/s,, decrease indicating an increase in the activation volume at a given zh. The microstructure sensitivity of this ordered L12 alloy is demonstrated by two prestrain experiments. First, a high temperature prestrain reduces the initial values of 1. 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,(AI,Hf)B single crystals.