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对锻态Ti-4.4Al-3.8Mo合金分别进行了β单相区和α+β两相区(相变点之下45℃)淬火处理,研究了亚稳相变对硬度的影响.结果表明,β单相区淬火处理的样品硬度比α+β两相区处理的样品高约10%.β单相区淬火后的相组成为全α′马氏体,自910℃的α+β两相区淬火后的相组成为等轴初生α相+α′马氏体+α″马氏体.硬度出现差异的主要原因是后者中存在硬度较低的初生α相和α″马氏体.本文修正了Ti-β稳定元素二元系亚稳相图(示意图),指出在α+α′和α+α″相区之间存在α+α′+α″相区,并使用修正后的相图解释了Ti-4.4Al-3.8Mo合金的相组成与硬度的关系.
The effects of metastable phase transformation on the hardness of Ti-4.4Al-3.8Mo alloy were studied by quenching the β-phase and α + β phases respectively at 45 ℃ under the transformation temperature.The results show that , the hardness of samples hardened by single-phase quenching is about 10% higher than that of samples treated by α + β two-phase region.The phase composition of β single-phase quenching is all α ’martensite, α + β from 910 ℃ Phase composition after quenching phase equiaxed primary α phase + α ’martensite + α’ martensite.The main reason for the difference in hardness is that there is a lower hardness of the latter primary α-phase and α “martensite In this paper, the metastable phase diagram of Ti-β stable element binary system is revised and the α + α ’+ α ”phase region exists between α + α’ and α + α" The phase diagram explains the phase composition and hardness of Ti-4.4Al-3.8Mo alloy.