Ti-6Al-4Cr(Mo)合金热处理显微组织的研究

Microstructures of Ti-6Al-4Cr (Mo) alloys during heat treatments

本文采用扫描电镜与透射电镜分析研究了Ti-6Al-4Cr和Ti-6Al-4Mo合金固溶和时效过程中显微组织的变化。结果表明:Ti-6Al-4Cr和Ti-6Al-4Mo合金经过相似的两相区固溶处理后,组织差别较大;两种合金经过β相区固溶后再时效,形成典型的魏氏组织,且硬度值较两相区处理的样品有很大提高;两种合金在相同热处理制度下,硬度值变化趋势相似,但前者的硬度值明显大于后者;Ti-6Al-4Cr合金在各种热处理条件下都有富Cr的固溶体区产生,经过1000℃/45min/空冷+600℃/2h/空冷处理后,有Laves相和界面相析出。

Microstructures of Ti-6Al-4Cr and Ti-6Al-4Mo alloys during the solid solution and aging were studied by SEM and TEM.The results showed that after α /β solution treatment,Ti-6Al-4Cr and Ti-6Al-4Mo alloys showed different microstructures.A similar Widmanstatten formed in two alloys after β solution and aging treatments.Their hardness greatly increased.Under the same heat- treatment system,the hardness of Ti-6Al-4Cr and Ti-6Al-4Mo alloys had a similar varying trend,but the former was significantly higher than the latter.There were some Cr solid solution in Ti-6Al-4Cr alloy.After 1 000 ℃ /45 min AC ＋ 600 ℃ /2 h AC treatments,Laves phase and interface phase appeared in Ti-6Al-4Cr.