粉末材料等径角挤扭成形显微组织与性能

以纯铝粉末和8.75vol%-SiC、35vol%-SiCp/Al基复合粉末材料为研究对象,分别在150℃和250℃温度下,采用粉末包套-等径角挤扭工艺,成功将粉末颗粒直接固结成高致密度的块体细晶材料。结果表明,变形后铝粉材料、8.75vol%和35vol%SiCp/Al基复合材料致密度分别为0.95、0.99和0.94;显微硬度分别为43HV、69HV和57HV,分别约为工业纯铝的1.3倍、1.7倍和2.0倍;复合材料成分分布及显微硬度均匀性在等径角挤扭强烈的剪切细化作用下得到显著改善;屈服强度分别为43.9MPa、120.1MPa和87.6MPa,抗压强度分别为54.8MPa、155.3MPa和122.7MPa,相比于致密体铝性能均有很大的提高;材料断口均以大小不一的基体铝片状断裂为主要特征。

Microstructure and properties of powder materials after equal channel angular pressing and torsion

Pure aluminum powder and 8.75vol%-SiC、35vol%-SiCp/Al particulate composites were successfully consolidated into near fully dense bulk materials with fine grains by powder in tubes-equal channel angular pressing and torsion(Pits-ECAPT) at 150℃ and 250℃ respectively.The density of the materials are 95%、99% and 94% respectively;the microhardness are 43.9HV、87.6HV and 120.1MPa,about 1.3、1.7 and 2.0 times that of industrial compact aluminum;the distribution of SiC particulates and the uniformity of microhardness are significantly improved.Compression test shows that the yield stress of the three materials are 43.9MPa、120.1MPa and 87.6MPa respectively,and the compressive strength are 54.8MPa、155.3MPa and 122.7MPa respectively.Those properties are much higher than that of industrial compact aluminum.Fracture surface are mainly featuring in sheet fracture of aluminum substrate with different sizes.