日本金属学会誌

J. Japan Inst. Metals, Vol. 59, No. 1 (1995),
pp. 23-30

Effect of Grain Size on High Temperature Deformation of Cu-30 mass%Zn Alloy

Akira Muto, Shoji Goto,Michihiro Tagami and Setuo Aso

Department of Materials Engineering and Applied Chemistry, Mining College, Akita University, Akita

Abstract:

Hot deformation and high ductility in fine-grained structures were studied via tensile tests of 70-30 brass specimens with different grain sizes (from 0.009 mm to 0.209 mm) at temperatures up to 803 K and at a strain rate of 6.7{×}10-4 s-1. The shapes of stress-strain curves were characterized by serrated flow and high temperature yielding phenomena. The shapes of stress-strain curves, yield stresses and tensile stresses strongly depended on initial grain size and temperature. Yield stresses, as well as tensile stresses at intermediate temperatures, increase in the region of finer grain, but decrease in the region of coarser grain with increasing grain size. The values of stress exponent n and activation energy Q in a mechanical equation [ε =A⋅ σn⋅ \exp (-Q/RT)] for fine-grained specimens were 3.9 and 120 kJ/mol, respectively. It is concluded from the above results that hot deformation as well as high ductility of α brass at intermediate temperatures can be controlled by the enhancement of grain boundary sliding and dynamic recrystallization.


(Received July 25, 1994)

Keywords:

high temperature deformation, α brass, grain size, hot ductility, intermediate temperature embrittlement, grain boundary sliding, dynamic recrystallization


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