ABSTRACT

Powder metallurgy (PM) Ti6Al4V alloy was prepared from HDH alloy powder by vacuum pressureless sintering. To study its high-temperature deformation behaviour, isothermal compression testing was carried out with temperature range of 900–1050°C, strain rate range of 0.01–10 s⁻¹, and compression ratio of 60%. Based on the hot deformation data, the corresponding constitutive equation and hot processing map were clarified. The deformation activation energy for PM Ti6Al4V alloy was 606.5 kJ mol⁻¹. Its deformation instability zone was very small, locating in the range of 960∼990°C with strain rate >1 s⁻¹. PM Ti6Al4V alloy had large hot working window and good hot workability. The ideal hot processing domain was at 970–990°C and 0.05–0.01 s⁻¹. Besides, the domain at 1000–1040°C and 1–10 s⁻¹ was also suitable for hot processing. This study proposed an effective guidance for the hot deformation (e.g. forging, extrusion, rolling) of PM Ti6Al4V alloy.

摘要

粉末冶金（PM）Ti6Al4V合金是由HDH合金粉末通过真空无压烧结制备的。为了研究其高温变形行为，进行了等温压缩试验，温度范围为 900-1050°C，应变速率范围为 0.01-10 s ^-1，压缩比为 60%。根据热变形数据，明确了相应的本构方程和热加工图。PM Ti6Al4V 合金的变形活化能为606.5 kJ mol ^-1。其变形不稳定区很小，位于960～990℃范围内，应变速率>1 s ^-1。PM Ti6Al4V合金具有较大的热加工窗口和良好的热加工性。理想的热加工域为 970–990°C 和 0.05–0.01 s ^-1. 此外，1000-1040°C 和 1-10 s ^{-1 的区域}也适合热加工。该研究为PM Ti6Al4V合金的热变形（如锻造、挤压、轧制）提供了有效的指导。