双连续相Mg-Ti复合材料的制备与力学性能

Preparation and Mechanical Properties of Bicontinuous Phase Mg-Ti Composite

采用增材制造与熔体渗透相结合的工艺制备了具有双连续相结构的Mg-Ti复合材料。研究了增材制造成形Ti-6Al-4V(TC4)多孔骨架增强体的孔结构类型和尺寸参数对孔隙率与力学性能的影响,使其兼具高孔隙率与良好力学强度。通过分析Mg-Ti复合材料的微观结构与界面结合机制,探究了钛合金骨架对其力学性能的强化作用。结果表明:Mg-Ti复合材料的抗压缩强度达到400 MPa,而其密度仅为2.56 g/cm3,具有用作轻量化结构材料的潜力。Mg-Ti复合材料的强度与未复合的Mg-9Al-1Zn(AZ91)合金基体相比提高了51%,这得益于Mg-Ti两相紧密的冶金结合界面,促进了载荷的有效传递。此外,双连续相结构引起的相互约束效应及钛合金骨架中超细针状α'-Ti马氏体引起的细晶强化对力学性能提升也做出了重要贡献。本研究采取的策略为复合材料的结构轻量化发展提供了新思路。

Mg-Ti composite with bicontinuous phase structure was prepared by the additive manufacturing(AM)coupled with the melt infiltration.The effects of pore structure type and size parameters on the porosity and mechanical properties of AM-prepared Ti-6Al-4V(TC4)porous scaffold reinforcement were investigated.By adjusting the size parameters,both high porosity and appreciable compressive strength can be achieved for the scaffold.The strengthening effect of titanium alloy scaffold on the mechanical properties of Mg-Ti composite was investigated by analyzing the microstructure and interface bonding mechanism.Results show that the Mg-Ti composite has high compressive strength of 400 MPa,whereas its density is only 2.56 g·cm^(−3),presenting the potential as lightweight structural materials.The strength of Mg-Ti composite is higher than that of raw Mg-9Al-1Zn(AZ91)alloy matrix by 51%.This enhancement is attributed to the tight metallurgical bonding interface between the scaffold and the matrix,which promotes the effective transfer of load.Additionally,the mutual constraint effect caused by the bicontinuous phase structure and the fine crystal strengthening caused by the ultra-fineα'-Ti martensite in TC4 scaffold also significantly contribute to the improvement of mechanical properties.The investigation strategy in this research provides a nouveau path for the development of structural lightweight composites.