通过热处理改善空心玻璃微球/镁合金(Mg-15Al-5Zn-1.5Cu)可溶复合材料的综合性能,采用金相显微镜和扫描电子显微镜等手段分析复合材料在热处理过程中的微观结构变化.通过压缩试验、浸泡试验和电化学测试等手段探究热处理条件对复合材料的力学性能和溶解行为的影响,并揭示其影响机理.结果表明,热处理主要通过影响Mg17Al12相和Al2CuMg相数量、形态和分布影响复合材料的力学性能和溶解速率;经420 ℃固溶处理20 h和200 ℃时效处理24 h后,复合材料的基体晶粒组织和析出相分布更加均匀,成分偏析和残余应力被消除.获得了优异的综合性能,极限抗压强度、布氏硬度和断裂应变分别可达435 MPa、HB 124和8.3%,室温下在3%KC1(质量分数)溶液中的平均溶解速率可达151 mg/(cm2·d),更有利于该复合材料在可溶井下工具中的应用.
This work focused on enhancing the comprehensive performance of a novel hollow glass microsphere reinforced Mg-15Al-5Zn-1.5Cu composites through heat treatment.Optical microscopy and scanning electron microscopy were employed to characterize the microstructure evolution.Using a combination of compression tests,immersion tests and electrochemical tests,the effects of heat treatment on mechanical properties,and degradation behavior,as well as the influence mechanisms were comprehensively examined.The results demonstrated that variations in the quantity and shape of the Mg17Al12 and Al2CuMg phases were primarily responsible for changes in the mechanical properties and degradation rate of the composites.After solution treatment at 420 ℃ for 20 h and aging at 200 ℃ for 24 h,the composites exhibited a more uniform microstructure and distribution of secondary phases,and the segregation and residual stress were also eliminated.This endowed the composites with a desirable overall performance:ultimate compressive strength of 435 MPa,hardness of HB 124,fracture strain of 8.3%,and degradation rate of 151 mg/(cm2.d)at room temperature,which made them more beneficial to the applications involving degradable downhole tools.