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激光熔化沉积 Ti60/高 Nb-TiAl 合金功能 梯度材料的成形行为与缺陷调控
Forming Behavior and Defect Controlof Ti60/High Nb-TiAl Functionally Graded Materials Fabricated by Laser Melting Deposition
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- DOI:
- 作者:
- 李瑞丰 1,丁洁 1,朱承飞 1,梁永锋 2,林均品 2
LI Ruifeng1,DING Jie1,ZHU Chengfei1,LIANG Yongfeng2,LIN Junpin2
- 作者单位:
- 1. 南京工业大学 材料科学与工程学院新材料研究院,江苏南京 210003;2. 北京科技大学 新金属材料全国重点实验 室,北京 100083
1. Tech Institute for Advanced Materials, College of Materials Science and Engineering, Nanjing Tech University, Nanjing 210003,China; 2. State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083,China
- 关键词:
- 激光熔化沉积;Ti 合金;TiAl 合金;功能梯度材料;沉积组织
laser melting deposition; Ti alloy; TiAl alloy; gradient material; deposited microstructure
- 摘要:
- 为满足航空发动机高温部件对轻量化与性能梯度化的迫切需求,本文采用激光熔化沉积(LMD)技术,系统研究了工艺参数对 Ti60 合金、高 Nb-TiAl 合金及其不同比例混合合金薄壁件成形质量的影响 ,并探索 Ti/TiAl 功能梯度材料(FGM)稳定成形的可行路径。 结果表明,Ti60 合金通过工艺优化可获得细小均匀且无明显缺陷的网篮组织 ;高Nb-TiAl 合金沉积过程中存在元素偏析,高能量输入易诱发气孔,而在较低功率下通过 300 ℃预热及连续沉积可有效抑制裂纹,获得细小全片层组织。 混合合金在合理能量输入下可实现无裂纹、无气孔成形。 直接过渡 Ti/TiAl 复合材料易在熔合线附近开裂,而通过逐级调整熔宽参数(Ti60、过渡区 A、过渡区 B 及 TiAl 的熔宽分别为 7.0、6.5、6.0、5.5 mm)构建功能梯度结构,可实现良好的组织与变形协调 ,功能梯度材料内部未观察到明显裂纹缺陷 。 双梯度结构(Ti/A/B/TiAl)由于引入更多成分过渡台阶,能进一步缓解界面处应力集中与硬度突变,表现出比单梯度结构更好的协调性和成形稳定性。To address the urgent demand for lightweight designs and performance gradations in high-temperature aeroengine components, this study employed laser melting deposition (LMD) to systematically investigate the influence of processing parameters on the forming quality of thin-walled components fabricated from Ti60 alloys, high-Nb-TiAl alloys, and their blended compositions and to explore feasible strategies for fabricating crack-free Ti/TiAl functionally graded materials (FGMs). The results demonstrate that with optimized parameters, Ti60 alloy develops a fine and uniform basket-weave microstructure without significant defects. For high Nb-TiAl alloys, elemental segregation occurs during deposition, and excessive energy input readily induces porosity. By preheating at 300 ℃ and adopting a continuous deposition strategy, cracking is effectively suppressed, resulting in a refined fully lamellar microstructure. Mixed alloys can be deposited without cracks or pores under appropriate energy input. While direct Ti/TiAl transition joints are prone to cracking near the fusion line, afunctionally graded structure fabricated through stepwise adjustment of the melt pool width (7.0 mm for Ti60, 6.5 mm for transition zone A, 6.0 mm for transition zone B, and 5.5 mm for TiAl) achieves good microstructural compatibility and deformation coordination, with no noticeable cracks observed within the graded region. Compared with single-gradient configurations, the double-gradient structure (Ti/A/B/TiAl), which introduces additional compositional transition steps, further mitigates interfacial stress concentration and abrupt changes in hardness, resulting in superior coordination and forming stability.











