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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。
At 573 K, the 7075Al / AZ31 composite plate was successfully prepared by equal channel corner extrusion. The effects of extrusion pass and annealing temperature on the interfacial layer structure and properties of the composite plate were investigated by SEM, EDS, XRD and shear tests. The composition of the shear fracture surface. The results show that the diffusion layer with a uniform thickness of 20μm is formed at the interface of composite plate prepared by 1-pass equal-angle channel extrusion, which consists of Al 3 Mg 2 phase and Mg 17 Al 12 phase. The thickness of Al 3 Mg 2 phase is Mg_ (17) Al_ (12) phase thickness (3μm) 5.6 times. After 2 passes, the thickness of diffusion layer did not change, but cracks appeared and the shear strength decreased sharply. The shear fracture surface occurred in Al 3 Mg 2 phase. The interface layer of the composite plate annealed at 473 K, the thickness of the diffusion layer did not change, the crack did not improve, and the shear strength increased slightly. In the annealing of 573 K, Al 3 Mg 2 phase and β-Mg 17 Al 12 phase in the diffusion layer of the composite plate, The phase layers are sharply thickened, the micro-cracks are welded and the shear strength drops sharply. Under the same treatment conditions, the shear strength of one-pass ECAP composite board was higher than that of two-pass ECAP composite board, and the strength was 30.11% after 473 K annealing treatment. After annealing at 573 K, the strength is 12.4% higher. Therefore, the 7075Al / AZ31 composite plate is prepared by the equal-channel angular extrusion method. The first pass is suitable and the annealing temperature of diffusion layer should not exceed 473K.