一种提高Ti5553合金综合性能的热加工方法

为了让Ti5553合金的强度和韧性等综合性能指标达到良好匹配,充分发挥其高强高韧的特点,提出了一种新的热加工方法。首先对Ti5553合金轧棒进行充分改锻,初步得到均匀、细小、无偏析、无β斑的基体组织,然后再利用β锻造形成一种细小密集的网篮组织,并在最后的β热处理过程中,生成β晶粒内的细小片状α转相和晶界处细小分散的α转相。结果表明:采用(Tβ-30)℃两相区改锻、(Tβ-30)℃预锻与(Tβ+20)℃β锻造的联合模锻以及(Tβ+35)℃退火+600℃时效的β热处理工艺后,可获得一种理想的β型钛合金组织,使该合金的强度、塑性和断裂韧性等综合性能指标都有所提高。

A Thermal Processing Method of Improving Comprehensive Performance of Ti5553 Alloy

In order to improve the comprehensive performance including strength and toughness of Ti5553 alloy, and give full play to its high strength and toughness characteristics, a novel thermal processing method was proposed. Rolled Ti5553 alloy bars were forged firstly, with the purpose of obtaining smaller, no segregation, no beta spot and uniform structure, and then formed the basket lattice structure through beta forging, after beta heat treatment process, smaller plate-like alpha transfer in beta grain size and small, scattered transfer alpha in grain boundary were generated. The results show that the ideal beta structure of titanium alloy can be obtained, and the comprehensive performance of Ti5553 alloy can be improved by the novel thermal process, which is forging in alpha ＋ beta phase of （ Tβ - 30） ℃ firstly, and then die forging at （ Tβ - 30） ℃ and （ Tβ ＋ 20） ℃ in turns, finally annealing at （ Tβ ＋ 35 ）℃ and aging at 600 ℃.