Deformationmechanismo_省略_yduringhotcompr.pdf

RARE METALS Vol. 26, No. 1, Feb 2007, p. 56 E-mail: rm@ Deformation mechanism of the spray formed 70Si30Al alloy during hot compression WEI Yanguang, XIONG Baiqing, ZHANG Yong’an, LIU Hongwei, WANG Feng, and ZHU Baohong State Key Laboratory for Fabrication Processing of Nonferrous Metals, General Research Institute for Nonferrous Metals, Beijing 100088, China (Received 2005-11-16) Abstract: The deformation mechanism of the spray formed 70Si30Al alloy was studied by hot compression on a Glee- ble-1500 test machine. It is shown that hot deformation of the spray formed 70Si30Al alloy is achieved by liquid flow due to isostatic pressure and movement of solid particles due to shear force. Deformation condition depends on the nucleation rate and closure rate of the cavities. The flow stress slightly varies when the difference between the nucleation rate and clo- sure rate of the cavities is small; however, it decreases when the nucleation rate of the cavities is greater than the closure rate of the cavities. Key words: 70Si30Al alloy; spray forming; hot compression; deformation mechanism [This study was financially supported by the National Basic Research Program of China (No. .] 1. Introduction tents limits the Si levels that can be achieved, in- creases brittleness, and decreases the thermal con- The novel spray formed 70Si30Al alloy devel- ductivity. It was anticipated that the limitations of oped for electronic packaging application has excel- casting and powder metallurgy might be mitigated lent physical characteristics [1-5], which include low by preparing them through a technology that pro- coefficient of thermal expansion (6.8 × 10−6 K−1) duces a fi