退火工艺对TC4钛合金板材组织和性能的影响

采用不同的退火工艺对热轧后的TC4板材进行热处理,对比分析了退火温度和退火时间对材料组织和性能的影响。结果表明,随着退火温度的升高,TC4钛合金板材的晶粒等轴化程度提高,抗拉强度和伸长率随温度升高变化不大,但是屈服强度下降明显,同时硬度有较大幅度的提高。温度高于900 ℃后,组织类型由等轴组织向双态组织转变。900 ℃保温4 h,组织中的晶粒迅速长大,延长保温时间可以提升TC4钛合金板材的塑性,对强度影响不大。950 ℃条件下延长保温时间,材料的硬度大幅度提高;低于900 ℃时延长保温时间,材料硬度的提高幅度较小。

Effect of annealing process on microstructure and properties of TC4 alloy sheet

Different annealing processes were used to heat treat the hot rolled TC4 sheet. The effects of annealing temperature and the holding time on the microstructure and properties of the sheet were analyzed and compared. The results show that the grain equiaxed degree of the TC4 sheet increases with the increase of annealing temperature,while the tensile strength and elongation change little,the yield strength decreases obviously and the hardness increases considerably. The microstructure changes from equiaxed to bimorphic type when the annealing temperature is higher than 900 ℃.When annealed at 900 ℃ for 4 h,the grain size increases rapidly,the plasticity can be improved by prolonging the holding time,while the strengths are affected a little. When the holding time is prolonged at 950 ℃,the hardness of the sheet increases greatly;when annealed below 900 ℃ and the holding time is prolonged,the hardness increases slightly.