激光沉积制造Ti65合金在热处理条件下的组织与力学性能演化
Microstructure and mechanical properties evolution of heat treated Ti65 alloy fabricated by laser deposition manufacturing
李长富 1葛坤 1李晓丹 2任宇航 1李播博 3杨光3
作者信息
- 1. 沈阳航空航天大学 航空制造工艺数字化国防重点学科实验室,沈阳 110136
- 2. 沈阳飞机工业(集团)股份有限公司,沈阳 110134
- 3. 沈阳航空航天大学 机电工程学院,沈阳 110136
- 折叠
摘要
对激光沉积制造的Ti65合金样品分别进行退火和固溶+时效热处理,并分析样品的显微形貌、元素分布与拉伸强度之间的内在联系.激光沉积制造Ti65合金在沉积态、退火态和固溶+时效态时,均以α片层组织为主,片层长宽比随热处理最高温度的增高而降低,固溶+时效态样品显微组织主要由α片层和β转变组织(βT)构成;其中的硅化物尺寸随热处理温度的增加而增加.(850℃,2 h,AC)退火处理后的样品具有最佳的室温和650℃拉伸性能.经固溶+时效热处理后,与退火态和沉积态样品相比,样品室温塑性最低,屈服强度和抗拉强度差最小,在650℃进行拉伸测试,样品表现出高塑性、低强度.硅化物中Zr、Nb、Ta、W等元素的富集,削弱了以上β稳定元素对α和β相的固溶强化作用,促进了更多硅化物的析出,致使合金具有相对较低的屈服强度和塑性,硅化物粗化富集后,对塑性破坏更加显著.
Abstract
Ti65 alloy samples prepared by laser deposition manufacturing technology(LDM)were treated by annealing,solution+aging heat treatment.The internal relationship between the microstructure,element distribution and tensile strength of the samples was comprehensively analyzed.The conclusions are as follows:the α lamellar structure is dominant in all of the Ti65 samples,including as deposited,annealed and solution+aged.The lamellar length-width ratio decreases with the increase of the maximum heat treatment temperature.Transformed β(βT)was found in solution+aging treated samples.The silicide was observed by TEM and its size increases with the increase of heat treatment temperature.The samples heat treated at 850℃for 2 h followed by air cooling(AC)show the best tensile properties at both room temperature and 650℃among the 5 group samples.For samples heat treated at 980℃,Nb,Ta,W and other elements are enriched in β phase,α laminar is not solid solution strengthened enough,while the size of silicide increases,the three factors result in the lowest plasticity and the lowest yield/tensile strength difference at room temperature,and high plasticity but insufficient strength at high temperature.The enrichment of Zr,Nb,Ta,W and other elements in the silicide weakens the solid solution strengthening effect of the above β-stable elements on the α and β phases,promotes the precipitation of more silicides,resulting in a relatively low yield strength and plasticity of the alloy.After the silicide is coarsened and enriched,the plastic damage is more significant.
关键词
Ti65钛合金/激光沉积制造/热处理/显微组织/力学性能Key words
Ti65 titanium alloy/laser deposition manufacturing/heat treatment/microstructure/mechanical property引用本文复制引用
基金项目
国家重点研发计划资助项目(2022YFB4600901)
出版年
2024
NETL
NSTL
万方数据