Abstract: As service conditions become harsh and performance requirements for components increase,single-phase Ti₃AlC₂ ceramics are difficult to meet the increasingly stringent requirements of modern industrial equipment because of their short comings of low toughness and poor wear resistance.It is urgent to develop effective methods for the controllable preparation of high-purity and small-particle size Ti₃AlC₂ solid solution powder and to fabricate Ti₃AlC₂ solid solution materials with good comprehensive mechanical properties.High-purity ultrafine Ti₃(Al_1.2-xSn_x)C₂(x=0,0.1,0.3 and 0.5) powders were prepared by mixing Ti,Al,Sn and TiC powders through the solid solution route in a planetary ball mill,two-step pressureless sintering and mechanical ball milling.Ti₃(Al_1.2-xSn_x)C₂ bulk samples were then prepared by spark plasma sintering.The results show that all the Ti₃(Al_1.2-xSn_x)C₂(x=0,0.1,0.3 and 0.5) powders have a purity of ＞99 mass% as well as a nano-layered structure.The mechanical properties of the Ti₃(Al_1.2-xSn_x)C₂ samples prepared by spark plasma sintering are greatly improved with the increase of the Sn solid solution,among which the Vickers hardness,bending strength,fracture toughness and compressive strength all increase first and then decrease.Sample Ti₃(Al_0.9Sn_0.3)C₂ has the best mechanical properties,with the Vickers hardness of 8.38 GPa,bending strength of 820.91 MPa,fracture toughness of 7.87 MPa·m^1/2 and compressive strength of 1 510 MPa.The improvement of the strength and hardness of Ti₃(Al_1.2-xSn_x)C₂ materials lies in solid solution strengthening and second phase strengthening,and the micro-characteristics of the materials,such as the layered structure,deflection of crack propagation and grain pull-out of the fracture surface,enhance the deformation and fracture resistance of the materials cooperatively.

Key words: Ti₃(Al_1.2-xSn_x)C₂, solid solution strengthening, pressureless sintering, spark plasma sintering, mechanical properties

摘要： 随着服役工况的恶劣和对部件性能要求的提高,单相Ti₃AlC₂陶瓷因低韧性和低耐磨性短板,已难以契合现代工业装备愈发严苛的要求。发展有效手段可控制备高纯度、小粒径的Ti₃AlC₂固溶体粉末,并制备出具有较好综合力学性能的Ti₃AlC₂固溶体材料刻不容缓。运用固溶途径,将Ti、Al、Sn、TiC粉末置于行星球磨机内混合,采用两步无压烧结法与机械球磨法制备了高纯超细的Ti₃(Al_1.2-xSn_x)C₂ (x分别为0、0.1、0.3和0.5) 粉末,并经放电等离子烧结制备了Ti₃(Al_1.2-xSn_x)C₂块状试样。结果表明:Ti₃(Al_1.2-xSn_x)C₂ (x分别为0、0.1、0.3 和0.5) 粉末纯度均＞99%(w),且呈现出纳米层状结构;放电等离子烧结制备的Ti₃(Al_1.2-xSn_x)C₂试样随着Sn固溶量的增加,力学性能均有较大提升,其中维氏硬度、抗弯强度、断裂韧性及抗压强度均呈现先增大后减小的趋势,Ti₃(Al_0.9Sn_0.3)C₂试样的力学性能最好,维氏硬度、抗弯强度、断裂韧性和抗压强度分别为8.38 GPa、820.91 MPa、7.87 MPa·m^1/2和1 510 MPa;Ti₃(Al_1.2-xSn_x)C₂材料强度与硬度的提升在于固溶强化与第二相强化,而材料的分层结构、裂纹扩展的偏转及断裂面的晶粒拉出等微观特性,协同增强了材料的抗变形与断裂能力。

关键词: Ti₃(Al_1.2-xSn_x)C₂, 固溶强化, 无压烧结, 放电等离子烧结, 力学性能