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在激光沉积Ti60A合金片状试样(40 mm×12 mm×3 mm)上进行一系列的循环热暴露模拟实验,每个循环包括红外加热120 s至最高800℃,随后压缩空冷60 s至最低150℃。采用OM、SEM及EDS分析了合金α相体积分数和β相长度,并测试其显微硬度随热暴露循环次数的变化。结果表明,随着热暴露循环次数的增加,激光沉积Ti60A合金从初始的网篮状β相和体积分数为78.5%的α相逐渐向楔形β相和粗大α相过渡,750次循环后转变为极少量颗粒状β相和体积分数为97.6%的大块α组织。讨论了特殊粗大α和破碎β组织的形成机理。经750次热暴露循环后的合金最硬,其显微硬度比沉积态的高33.3%。
A series of cyclic thermal exposure simulations were performed on laser-deposited Ti60A alloy flake specimens (40 mm × 12 mm × 3 mm) with each cycle including infrared heating for 120 s up to 800 ° C followed by air-cooling for 60 s 150 ° C. The volume fraction of α phase and the length of β phase were analyzed by OM, SEM and EDS. The changes of microhardness with the number of heat exposure cycles were also tested. The results show that with the increase of heat exposure cycles, laser-deposited Ti60A alloy gradually transitions from the initial networked β-phase and the α-phase with a volume fraction of 78.5% to the wedged β-phase and the coarse α-phase. After 750 cycles, A very small amount of granular β phase and a volume fraction of 97.6% bulk α tissue. The formation mechanism of special coarse α and broken β tissue was discussed. After 750 cycles of exposure to heat the hardest alloy, the microhardness 33.3% higher than the deposition state.