稀土元素La对粉末冶金钛合金锻态组织与力学性能的影响

Effect of rare earth-La addition on microstructure and mechanical property of powder forged Ti alloy

分别以添加LaH2和LaB6的方式在钛合金中引入稀土元素La,采用粉末锻造法制备Ti-Fe-Mo-La合金,研究La的添加方式对钛合金组织与性能的影响。结果表明,添加LaH2可显著提高钛合金的伸长率,其中添加0.3%LaH2的合金伸长率达26.5%,比未添加LaH2的合金提高4倍以上,但强度减少约50 MPa左右;添加LaB6可显著提高合金强度,其中添加0.15%LaB6的合金抗拉强度达1 100 MPa,但伸长率提高不明显。以不同方式添加稀土La形成的微观组织造成的强化机制不同是材料强度和塑性变化的主要原因。

Ti-Fe-Mo alloys with rare earth La addition were fabricated by powder forging. The rare earth La were added in the form of LaH2 and LaB6. The results show that the elongation of the alloy greatly increased by addition of LaH2, but the strength of the alloy slightly decreased. However, the strength obviously increased by addition of LaB6, and the elongation slightly increased. The elongation of the alloy by addition of 0.3%LaH2 reached 26.5%, which is four times of that of the original alloy. The strength of the alloy by addition of LaB6 reached 1 100 MPa. The different hardening mechanisms due to different microstructure formed by addition of LaH2 and LaB6 are the main reasons for the change of strength and elongation.