碳化物与钛合金层协同强韧化TiAl基叠层复合板材的微观组织及力学性能

Microstructure and Mechanical Properties of TiAl Laminated Composite Sheets Reinforced by Carbides and Titanium Alloy Layer

叠层复合设计是突破传统金属基复合材料强韧性失配瓶颈的有效途径。基于仿生学原理,通过碳化物和通孔构型钛合金层协同增强制备了TiAl基叠层复合板材,并研究了该复合板的微观组织和力学性能,采用XRD、SEM、EBSD及三点弯曲法等分析了复合板材的相组成、微观结构,并测量其弯曲强度和断裂韧性。结果表明,复合板材主要由Ti_(2)AlC、α_(2)-Ti_(3)Al、γ-TiAl和少量的TiC相组成。当Ti_(2)AlC含量为0wt%时,复合板材的性能最佳,呈各向异性,平行叠层方向的弯曲强度和断裂韧性分别为1165.35 MPa和34.90 MPa·m^(1/2),垂直叠层方向的弯曲强度和断裂韧性分别为722.68 MPa和28.55 MPa·m^(1/2)。随着Ti_(2)AlC含量的增大,垂直和平行叠层方向的性能实现了近各向同性。结论可为金属基复合材料的仿生复合设计、优化和工程应用提供理论依据和技术支撑。

It is an effective way to break through the bottleneck of strength and toughness mismatch of traditional metal-matrix composites by laminated structure composite design.Based on the bionics principle,the TiAl laminate composite plate was prepared by the collaborative enhancement of carbide and through-hole structure titanium alloy layer.The microstructure and mechanical properties of the composite sheets were also studied.The phase composition and microstructure of the composite plate were analyzed by XRD,SEM,EBSD were measured and its bending strength and fracture toughness by three-point bending methods.The results show that the composition of the composite layers are composed of Ti_(2)AlC,α_(2)-Ti_(3)Al,γ-TiAl and a small amount of TiC phases.When the content of Ti_(2)AlC is 0wt%,the mechanical properties of the sheet present anisotropic feature and achieve optimum values,and the flexural strength and fracture toughness are 1165.35 MPa and 34.90 MPa·m^(1/2) when stress is parallel to the laminated structure,and 722.68 MPa and 28.55 MPa·m^(1/2) when stress is perpendicular to the laminated structure,respectively.With the increase of the content of Ti_(2)AlC,the properties of the sheets are nearly isotropic.It provides theoretical basis and technical support for biomimetic composite design,optimization and engineering application of heterogeneous metal-matrix composites.