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

作　　者：张永忠[1] 黄灿[1] 吴复尧[2] 刘黎明[2] 

机构地区：[1]北京有色金属研究总院复合材料中心,北京100088 [2]中国航天科工集团航天特种材料及工艺技术研究所,北京100074

出　　处：《中国激光》2010年第10期2684-2688,共5页Chinese Journal of Lasers

基　　金：国家973计划(2006CB605206-1);国家自然科学基金(50871023)资助课题

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2α+γ的层片状晶团及少量γ相组成,层片晶团的尺寸约10μm;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810MPa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。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.

关 键 词：激光技术 激光熔化沉积 Γ-TIAL合金 微观组织 力学性能 

分 类 号：TN249[电子电信—物理电子学] TF124[冶金工程—粉末冶金]