定向凝固Ti-(43-48)Al-2Cr-2Nb合金的显微组织和性能

Microstructure and Properties of Ti-(43-48)Al-2Cr-2Nb Alloy Prepared by Directional Solidification

研究了Al含量对冷坩埚定向凝固Ti-(43-48)Al-2Cr-2Nb合金的显微组织和力学性能的影响。结果表明,Ti-(43-48)Al-2Cr-2Nb合金的定向凝固组织主要由α2相和γ相组成,随着Al含量的提高α2相逐渐减少而γ相含量提高,且其显微组织片层由以平行片层和45°片层为主的混合片层向垂直混合片层转变;Al含量(48%,原子分数)较高的Ti-(43-48)Al-2Cr-2Nb合金其片层取向与应力方向垂直,具有较高的抗压强度和较低的塑性;Al含量(45%,原子分数)适中的合金其片层取向与应力方向平行,具有较高的强度、室温延伸率和综合性能。

The effect of Al content on the microstructure and mechanical properties of directionally solidified Ti-(43-48)Al-2 Cr-2 Nb alloy prepared by cold crucible was investigated.The results show that the directional solidification structure is mainly composed ofα2-phase andγ-phase.With the increase of Al content,theα2-phase decreases and theγ-phase content increases,while the direction of microstructural lamellae changed from parallel lamellae and 45°lamellae to vertical lamellae;For the alloy with48%Al(atomic fraction),the orientation of lamellae is perpendicular to the direction of stress,its compressive strength is high,but plasticity is low;For the alloy with 45%Al(atomic fraction),the orientation of lamellae is parallel to the direction of stress,while maintaining high strength,the room temperature elongation is also high,in other word,the comprehensive properties are good.