1 Q. Gu, J. Van Humbeeck and L. Delaey, Functional Mater. 25(6) (1994) 505. 2 Z. Wang, W. Cai and L.C. Zhao, J. Mater. 14 (1998) 182. 3 K. Tanaka, T. Hayashi, F.D. Fischer and B. Buchmayr, Z. Metallkde 85(2) (1994) 122. 4 K. Tsuzaki, Y. Netsume, Y. Kurokawa and T. Maki, Scripta Metall. (27) (1992) 471. 5 N. Li and Y.H. Wen, Mater. Mech. Eng. 20(4) (1996) 20 (in Chinese). 6 S.M. Tan, J.H. Lao and S.W. Yang, Scripta Metall. (25) (1991) 2163. 7 W.M. Zhou, Scr. Mater, 39 (1998) 1483. 8 C.X. Zhao, Metall.Trans. 30 (1999) 2599. 9 Z.H. Guo, Y.H. Rong, S.P. Chen and Z.Y. Xu, J. Shanghai Jiaotong Univ. 32(2) (1998) 41 Chinese). 10 J.H. Yang, Ada Metall. 40(8) (1998) 2011. 11 L.J. Rong, Y.Y. Li and C.X. Shi, Scripta Metall. 34(6) (1996) 993. 12 C.Y. Chung, S.C. Chen and T.Y. Hsu, Elsevier Science (4) (1996) 227.