Hot deformation behavior and processing maps of fine-grained SiCp/AZ91 composite

摘要

Hot deformation behavior of fine-grained SiCp/AZ91 composite was investigated at the temperature of 543-693 K and strain rate of 0.001-1 s~(-1). Processing maps based on dynamic material model (DMM) were developed at the strain of 0.1-0.5. Both the optimum process conditions and the dominant flow instability mechanism of fine-grained SiCp/AZ91 composite were given and analyzed. To describe the hot deformation behavior of fine-grained SiCp/AZ91 composite more exactly, the stress calculated by three typical constructive equations was compared with the measured value. The results show that the power law is deduced to be the most suitable constructive relationship for fine-grained SiCp/AZ91 composite, which is unlike previous reports. The calculated Q value increases with increasing temperature and strain rate. At 0.001 s~(-1), the deformation mechanism of the composite is deduced to be grain boundary diffusion controlled dislocation climb; while, the deformation mechanism is deduced to be dislocation climb at 0.1-1 s~(-1).