挤压铸造压力对超声辅助成形纳米SiCp/Al-Cu复合材料颗粒分布与力学性能的影响

Influence of squeeze casting pressure on nanoparticle distribution and mechanical properties of nano-SiCp/Al−Cu composites assisted with ultrasonic vibration

采用超声振动技术制备2%(质量分数)纳米SiCp/Al-Cu复合材料浆料,并研究挤压铸造压力对纳米SiCp/Al-Cu复合材料颗粒分布和力学性能的影响。研究发现,随着挤压压力从0增至400 MPa,合金α(Al)晶粒尺寸先大幅降低而后下降趋势变缓,并且铸件中孔隙率明显降低。当挤压压力为400 MPa时,α(Al)晶粒尺寸从105μm减小到25μm,纳米SiCp分布得到明显改善,以致其力学性能最佳。复合材料的抗拉强度、屈服强度和伸长率分别为290 MPa、182 MPa和10%,相比于重力铸造(0 MPa)分别提高52.6%、25.5%和400%。在高压作用下,纳米SiCp/Al-Cu复合材料强度和伸长率的提高归因于晶粒细化、孔隙率降低和纳米颗粒均匀分布。

The influence of squeeze casting pressure on nanoparticle distribution and mechanical properties of 2 wt.%nano-SiCp/Al−Cu composites assisted with ultrasonic vibration was investigated.Results show that as the applied pressure increases from 0 to 400 MPa,theα(Al)grains are significantly refined at first and then the refinement trend slows down,and the porosity of composites is gradually reduced.When the applied pressure is 400 MPa,α(Al)grain size is reduced from 105 to 25μm,and the nanoparticle distribution is significantly improved,resulting in the optimal mechanical properties of the composites.The ultimate tensile strength,yield strength and elongation of the composites are 290 MPa,182 MPa and 10%,which are 52.6%,25.5%and 400%higher than those of the nano-SiCp/Al−Cu composites prepared by gravity casting(0 MPa).The enhancement in strength and elongation of nano-SiCp/Al−Cu composites under high pressure is mainly attributed to grain refinement,reduction of porosity and uniform distribution of nanoparticles.