J. Mater. Sci. Technol. ›› 2019, Vol. 35 ›› Issue (8): 1578-1586.DOI: 10.1016/j.jmst.2019.04.008

• Orginal Article • Previous Articles     Next Articles

Static coarsening behaviour of lamellar microstructure in selective laser melted Ti-6Al-4V

Sheng Caoab, Qiaodan Huc, Aijun Huangab*(), Zhuoer Chenb, Ming Suna, Jiahua Zhanga, Chenxi Fub, Qingbo Jiab, Chao Voon Samuel Limb, Rodney R.Boyerb, Yi Yanga*(), Xinhua Wub   

  1. a School of Materials Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
    b Monash Centre for Additive Manufacturing (MCAM), Monash University, Clayton, VIC 3800, Australia
    c School of Materials Science and Engineering, Shanghai Jiao Tong University, 200240 Shanghai, China
  • Received:2018-09-28 Revised:2018-12-30 Accepted:2019-01-26 Online:2019-08-05 Published:2019-06-19
  • Contact: Huang Aijun,Yang Yi
  • About author:

    1 These authors contributed equally to this work.

Abstract:

Static coarsening mechanism of selective laser melted (SLMed) Ti-6Al-4V with a lamellar microstructure was established at temperatures from 700 °C to 950 °C. Microstructure evolution revealed that high heat treatment temperature facilitated martensite decomposition and promoted lamellae growth. At each temperature, the growth rate decreased with increasing holding time. The static coarsening behaviour of SLMed Ti-6Al-4V can be interpreted by Lifshitz, Slyozov, and Wagner (LSW) theory. The coarsening coefficient were 0.33, 0.33-0.4, 0.4-0.5 for 700-800 °C, 900 °C and 950 °C, respectively. This indicated the coarsening mechanism was bulk diffusion at 700-800 °C, and a combination of bulk diffusion and interface reaction at 900 °C and 950 °C conditions.

Key words: Selective laser melting, Ti-6Al-4V, Microstructure, Heat treatment