1. Laboratory of Metallurgy and MaterialsCollege of Materials Science and EngineeringChongqing University Chongqing 400030 P. R. China
2. Chongqing Key Laboratory of Vanadium-Titanium Metallurgy and New MaterialsChongqing University Chongqing 400030 P. R. China
3. Department of Materials Science and EngineeringKTH Royal of Technology Stockholm, SE 10044 Sweden