Cerri Emanuela, Ghio Emanuele
Department of Engineering for Industrial Systems and Technologies, University of Parma, Via G. Usberti, 181/A, 43124 Parma, Italy.
Materials (Basel). 2024 Jul 9;17(14):3401. doi: 10.3390/ma17143401.
Laser powder bed-fused Ti6Al4V alloy has numerous applications in biomedical and aerospace industries due to its high strength-to-weight ratio. The brittle α'-martensite laths confer both the highest yield and ultimate tensile strengths; however, they result in low elongation. Several post-process heat treatments must be considered to improve both the ductility behavior and the work-hardening of as-built Ti6Al4V alloy, especially for aerospace applications. The present paper aims to evaluate the work-hardening behavior and the ductility of laser powder bed-fused Ti6Al4V alloy heat-treated below (704 and 740 °C) and above (1050 °C) the β-transus temperature. Microstructural analysis was carried out using an optical microscope, while the work-hardening investigations were based on the fundamentals of mechanical metallurgy. The work-hardening rate of annealed Ti6Al4V samples is higher than that observed in the solution-heat-treated alloy. The recrystallized microstructure indeed shows higher work-hardening capacity and lower dynamic recovery. The Considère criterion demonstrates that all analyzed samples reached necking instability conditions, and uniform elongations (>7.8%) increased with heat-treatment temperatures.
激光粉末床熔融Ti6Al4V合金因其高强度重量比在生物医学和航空航天工业中有众多应用。脆性的α'-马氏体板条赋予了最高的屈服强度和极限抗拉强度；然而，它们导致伸长率较低。必须考虑几种后处理热处理方法来改善增材制造Ti6Al4V合金的延展性和加工硬化，特别是对于航空航天应用。本文旨在评估在β转变温度以下（704和740°C）和以上（1050°C）进行热处理的激光粉末床熔融Ti6Al4V合金的加工硬化行为和延展性。使用光学显微镜进行微观结构分析，而加工硬化研究基于机械冶金学原理。退火Ti6Al4V样品的加工硬化率高于固溶热处理合金中的观察值。再结晶微观结构确实显示出更高的加工硬化能力和更低的动态回复。Considère准则表明，所有分析样品均达到颈缩失稳条件，并且均匀伸长率（>7.8%）随热处理温度升高而增加。
