Natural Science Foundation for Key Program( 50935007 ) ;Natural Science Foundation (50805121); National Basic Research Program of China (2010CB731701);Foundation for Fundamental Research of Northwestern Polytechnical University in PR China (NPU-FFR-JC20100229);Research Fund of the State Key Laboratory of Solidification Processing of Northwestern Polytechnical University in PR China (27-TZ-2010 ); the 111 Project (B08040)