退火温度对低成本TC4LCA钛合金板材组织和性能的影响

为提高低成本TC4LCA钛合金板材的强度和冲击性能,选取不同退火温度对典型规格板材进行热处理,研究了其显微组织和力学性能的变化规律,分析了显微组织对强度和冲击性能的影响。结果表明,随着退火温度的升高,TC4LCA钛合金中的长条状初生α相转变为等轴状,β转变组织中析出针状或片状次生α相;退火温度越高,长条状初生α相含量减少,等轴化倾向明显,直至发生粗化;针状或片状次生α相长大。合金的强度先增大后减小、断后伸长率略有降低,冲击吸收能量则呈增大趋势。综合考虑,在800～880 ℃范围进行退火可使TC4LCA钛合金板材获得强度、塑韧性的最佳匹配。

Effect of annealing temperature on microstructure and properties of low cost TC4LCA titanium alloy plate

In order to improve the strength and impact properties of the low cost TC4LCA titanium alloy plate, different annealing temperatures were selected for heat treatment of the plate with typical dimensions. After annealing, the change law of the microstructure and properties of the alloy was investigated, and the effect of microstructure on strength and impact properties was analyzed. The results show that the long strip primary α phase transforms to be equiaxed with the increase of annealing temperature, meanwhile, the acicular or flake secondary α phase is precipitated from the β transformation microstructure. With the increase of annealing temperature, the long strip primary α phase decreases in amount and tends to be equiaxed obviously until to its coarsening, and the acicular or flake secondary α phase grows up. When the annealing temperature increases, the strength of the alloy first increases and then decreases, the elongation after fracture decreases slightly, while the impact absorbed energy increases. For comprehensive consideration, the strengths, plasticity and toughness of the TC4LCA titanium alloy plates can get optimum match when the annealing temperature is in the range of 800-880 ℃.