中国激光, 2010, 37 (10): 2684, 网络出版: 2010-09-25
激光熔化沉积γ-TiAl合金的组织及力学性能
Microstructure and Mechanical Properties of Laser Direct Deposited γ-TiAl Alloy
激光技术 激光熔化沉积 γ-TiAl合金 微观组织 力学性能 laser technique laser direct deposition γ-TiAl alloy microstructure mechanical properties
摘要
通过激光熔化同步输送的Ti-47Al-2Cr-2Nb-0.5W-0.15B合金粉末,在TC4钛合金基板上逐层沉积制备出γ-TiAl合金的薄壁样品,分析了所沉积材料的开裂行为、微观组织、相组成及力学性能。结果表明,激光熔化沉积的γ-TiAl合金具有较高的开裂倾向,缩短激光扫描沉积的长度及引入具有较高韧性的钛合金作为过渡材料,可大大减缓薄壁沉积时的温度梯度和热应力,从而避免开裂的发生;激光熔化沉积γ-TiAl合金的内部组织致密,由α2+γ的层片状晶团及少量γ相组成,层片晶团的尺寸约10 μm;沉积状态下,沿薄壁长度及高度方向的室温抗拉强度分别为810 MPa和575 MPa,沿高度方向750 ℃下和长度方向850 ℃下的高温拉伸强度分别为550 MPa 和625 MPa。
Abstract
Thin wall samples from γ-TiAl(Ti-47Al-2Cr-2Nb-0.5W-0.15B)alloy are prepared on substrate of TC4 titanium alloy by laser direct deposition of coaxially fed metallic powders. The cracking behavior, microstructure, phase constitution, and mechanical properties of the deposited materials are investigated. The results indicate that the deposited γ-TiAl alloy presents high tendency for cracking. Decreasing the deposited wall length or introducing ductile titanium alloy as transition materials will mitigate the temperature gradient and thermal stress during deposition, thus avoid cracking. Laser direct deposited γ-TiAl alloy are full dense, composed of α2+γ lamellar colony and small amount of γ single phase. The size of the lamellar colony is about 10 μm. For as-deposited γ-TiAl alloy, the room-temperature tensile strengths are 810 MPa and 575 MPa along the longitude and build-up direction respectively, and the tensile strength under 750 ℃ along the build-up direction is 550 MPa and under 850 ℃ along longitude direction is 625 MPa.
张永忠, 黄灿, 吴复尧, 刘黎明. 激光熔化沉积γ-TiAl合金的组织及力学性能[J]. 中国激光, 2010, 37(10): 2684. Zhang Yongzhong, Huang Can, Wu Fuyao, Liu Liming. Microstructure and Mechanical Properties of Laser Direct Deposited γ-TiAl Alloy[J]. Chinese Journal of Lasers, 2010, 37(10): 2684.