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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-walled samples of γ-TiAl alloy were deposited layer by layer on TC4 titanium alloy substrate by laser melting Ti-47Al-2Cr-2Nb-0.5W-0.15B alloy powder. The cracking behavior of the deposited materials , Microstructure, phase composition and mechanical properties. The results show that laser melting γ-TiAl alloy has high tendency of cracking, shortening the length of laser scanning deposition and introducing titanium alloy with higher toughness as transition material, which can greatly reduce the temperature gradient and thermal stress during thin-wall deposition , So as to avoid the occurrence of cracking. The internal structure of the γ-TiAl alloy deposited by laser melting was dense and consisted of 2α + γ lamellar and a few γ phases. The size of the lamella was about 10μm. The tensile strength at room temperature of wall length and height direction are 810 MPa and 575 MPa, respectively. The tensile strength at high temperature of 750 ° C and 850 ° C along the height direction is 550 MPa and 625 MPa, respectively.