等通道转角挤压制备7075Al/AZ31复合板界面组织及结合强度  

Interfacial microstructure and bonding strength of 7075Al/AZ31 composite plates fabricated by equal channel angular pressing

作　　者：任广笑 王红霞[1,2] 周斌[1,2] 刘一鸣[1,2] 王斌兵 

机构地区：[1]太原理工大学材料科学与工程学院,山西太原030024 [2]山西省先进镁基材料重点实验室,山西太原030024 [3]太原市精诚镁合金科技有限公司,山西太原030024

出　　处：《材料热处理学报》2016年第5期33-39,共7页Transactions of Materials and Heat Treatment

基　　金：国家自然科学基金(51301118);山西省国际合作项目(2014081002);山西省高等学校科技创新项目(2013108)

摘　　要：在573 K,通过等通道转角挤压成功制备了7075Al/AZ31复合板,并采用SEM、EDS、XRD和剪切实验研究了挤压道次及退火温度对复合板界面层组织和性能的影响及剪切断裂面的组成。结果表明:1道次等通道转角挤压制备的复合板界面处形成厚度为20μm均匀致密的扩散层,由Al_3Mg_2相和Mg_(17)Al_(12)相组成,Al_3Mg_2相层厚(17μm)是Mg_(17)Al_(12)相层厚(3μm)的5.6倍。2道次等通道挤压后,扩散层厚度无变化,但是出现了裂纹,剪切强度大幅下降,剪切断裂面发生在Al_3Mg_2相层。复合板界面层在473 K退火,扩散层厚度无变化,裂纹无改善,剪切强度略有提高;573 K退火,复合板扩散层中的Al_3Mg_2相层和β-Mg_(17)Al_(12)相层均急剧增厚,微裂纹被焊合,剪切强度均大幅下降。在相同处理状态下,1道次ECAP复合板剪切强度均高于2道次ECAP复合板,473 K退火处理后,强度高出30.11%。573 K退火处理后,强度高出12.4%。故利用等通道转角挤压法制备7075Al/AZ31复合板,1道次比较合适,扩散层退火温度不宜超过473 K。7075Al / AZ31 laminated composites were successfully fabricated by equal channel angular processing（ ECAP） at 573 K. The effect of ECAP passes and annealing temperature on microstructure evolution,phase constituent and bonding strength near the joining interface of the laminated composites was studied by means of scanning electron microscopy,X-ray diffraction and shear tests. The results indicate that diffusion layer with thickness of 20 μm is observed at the joining interface of the laminated composites prepared by one ECAP pass. The diffusion layer is mainly composed of Al_3Mg_2 and β-Mg_（17）Al_（12） phases. After two ECAP passes,the change of the diffusion layer thickness is not obvious,while the formation of crack in the diffusion layer leads to the bonding strength decreasing. After annealing at 473 K,the thickness of the diffusion layer and the crack remains unchange,while the bonding strength increass slightly. However,with increasing the annealing temperature to 573 K,the thickness of the diffusion layer increases rapidly,and the bonding strength decreases.The laminated composite fabricated by one ECAP pass presents higher bonding strength than that of fabricated by two ECAP passes after annealing under the same condition. Therefore,the processing parameters of one pass ECAP and annealing at 473 K are recommended to fabricate the 7075 A / AZ31 laminated composite plates.

关 键 词：复合板 等通道转角挤压 界面微观组织 结合强度 

分 类 号：TG146.2[一般工业技术—材料科学与工程]