Static coarsening behaviour of lamellar microstructure in selective laser melted Ti–6Al–4V. Issue 8 (August 2019)

• Record Type: Journal Article
• Authors: Cao, Sheng; Hu, Qiaodan; Huang, Aijun; Chen, Zhuoer; Sun, Ming; Zhang, Jiahua; Fu, Chenxi; Jia, Qingbo; Lim, Chao Voon Samuel; Boyer, Rodney R.; Yang, Yi; Wu, Xinhua
• Is Part Of: Journal of materials science & technology. Volume 35:Issue 8(2019)
• Page Start: 1578
• Page End: 1586
• Publication Date: 2019-08
• Subjects: Selective laser melting -- Ti–6Al–4V -- Microstructure -- Heat treatment; Metals -- Periodicals; Materials science -- Periodicals; Materials science; Metals; Periodicals; 620.1105
• DOI: 10.1016/j.jmst.2019.04.008
• Languages: English
• ISSNs: 1005-0302

Abstract

Highlights: The hardness of heat treated SLMed Ti-6Al-4V and lamellar width obey the Hall-Petch relationship. The lamellae coarsening behaviour of SLMed Ti-6Al-4V can be interpreted by LSW theory. The coarsening mechanism is identified from 700 to 950 °C for SLMed Ti-6Al-4V. 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.