H.B. Chang;Z.G. Li; T. Y. Hsu ;Z. Y. Xu; and X. Y. Ruan (Department of Metallurgical Engineering, Shanghai Technical College of Metallurgy, Shanghai 200233,China)(Department of Plasticity Technology, Shanghai Jiao Tong University, Shanghai 200030, China)(Department of Materials Science, Shanghai Jiao Tong University, Shanghai 200030, China)