ZENG Xianghua,SHA Jiande,SU Ge Institute of Metal Research,Academia Sinica,Shenyang,ChinaYUAN Jigang LIU Fumei ZHONG Huiwen Southwest Aluminium Mill,China National Nonferrous Metals Industry Corporation,Chongqing,China SHA Jiande,Engineer,Institute of Metal Research,Academia Sinica,Shenyang,China