等径角挤扭对SiC_p/Al复合材料微观结构及力学性能的影响

以SiC_p/Al复合粉末为研究对象,开展不同变形程度的等径角挤扭(ECAPT)变形实验,研究等径角挤扭对SiC_p/Al复合材料微观结构及力学性能的影响。利用OM、XRD、TEM和XPS以及排水测密度法、力学性能测试等手段分析不同试样的微观组织和力学性能的演变规律以及界面反应情况。结果表明:随变形道次增加,Si C团聚现象得到改善,微晶尺寸逐渐减小,位错密度逐渐增大;材料界面处发生保护反应生成Al_2O_3,且反应程度随变形道次增加而加剧,未发生有害的界面反应,无Al_4C_3脆性相生成。4道次变形后材料的显微硬度和屈服强度相比1道次分别提高10%和16%。

Effect of equal channel angular pressing and torsion on microstructure and mechanical properties of SiCp/Al composite

The severe plastic deformation can make a great difference to the microstructure and mechanical properties of materials. In this paper, based on the SiCp/Al composite powder, different ECAPT deformation processes in various severities were carried out. The microstructure evolution, mechanical properties and interfacial reaction of different samples were analyzed by OM, XRD, TEM and XPS, as well as draining method and mechanical property test. The results show that the agglomeration of particles and the dislocation density of the samples improve evidently and the crystallite sizes decrease with increasing the passes number. Protective reaction of SiO2 and Al occurs at the interface, and the degree raises with the passes number. There is no harmful chemical reaction and no brittle phase of Al4C3 appearing at the interface. The microhardness and yield strength of the material improve 10% and 16% respectively after 4 passes deformation, compared with 1 pass deformation material.