J. Mater. Sci. Technol. ›› 2018, Vol. 34 ›› Issue (12): 2316-2324.DOI: 10.1016/j.jmst.2018.05.011

• Orginal Article • Previous Articles     Next Articles

Effects of Zr, Ti and Sc additions on the microstructure and mechanical properties of Al-0.4Cu-0.14Si-0.05Mg-0.2Fe alloys

Jian Fenga, Bing Yea*(), Lijie Zuoa, Ruijuan Qib*(), Qudong Wanga, Haiyan Jianga, Rong Huangb, Wenjiang Dinga, Jie Yaoc, Chuntao Wangc   

  1. a National Engineering Research Center of Light Alloy Net Forming and State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
    b Key Laboratory of Polar Materials and Devices, Ministry of Education, East China Normal University, Shanghai, 200062, China
    c Ningbo Heli Mould Technology Co., Ltd, 358 Xigu Road, Industrial Park, Xiangshan County, Zhejiang, 315700, China
  • Received:2018-01-19 Revised:2018-04-06 Accepted:2018-04-25 Online:2018-12-20 Published:2018-11-15
  • Contact: Ye Bing,Qi Ruijuan

Abstract:

The evolution of microstructure and mechanical properties of Al-0.4Cu-0.14Si-0.05Mg-0.2Fe (wt.%) alloys, micro-alloyed with Zr, Ti and Sc, were investigated. The addition of 0.2%Zr to base alloy accelerates the precipitation of Si-rich nano-phase in α-Al matrix, which plays an important role in improving the mechanical properties of an alloy. The tensile strength increases from 102 MPa for the base alloy to 113 MPa for the Zr-modified alloy. Adding 0.2%Zr + 0.2%Ti to base alloy effectively refines α-Al grain size and accelerates the precipitation of Si and Cu elements, leading to heavy segregation at grain boundary. By further adding 0.2%Sc to Zr + Ti modified alloy, the segregation of Si and Cu elements is suppressed and more Si and Cu precipitates appeared in α-Al matrix. Accompanied with the formation of coherent Al3Sc phase, the tensile strength increases from 108 MPa for the Zr + Ti modified alloy to 152 MPa for the Sc-modified alloy. Due to excellent thermal stability of Al3Sc phase, the Sc-modified alloy exhibits obvious precipitation hardening behavior at 350 °C, and the tensile strength increases to 203 MPa after holding at 350 °C for 200 h.

Key words: Micro-alloying, Microstructure, Mechanical properties, Al3Sc, Grain size