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采用包覆法制备W-5%(质量分数)Re复合粉末,采用气氛保护等离子喷涂成形技术制备某实验型固体火箭发动机喷管(Solid Rocket Motor,SRM),研究2300℃真空烧结时喷管致密度﹑组织结构及显微硬度﹑抗拉强度、压缩强度等性能随烧结时间的变化规律。研究表明:喷涂成形件为典型的柱状晶层片结构,粒子层片结合部位存在较多孔隙及微观缝隙,成形件致密度为87.5%,其显微硬度﹑抗拉强度、压缩强度分别为321.8 HV_(0.025),57.9 MPa及390.2MPa。随着真空烧结时间由2 h延长至6 h及8 h,W-Re合金逐渐由定向凝固柱状晶层片结构转化为颗粒状结构,致密度及力学性能均随之提高。其中经8 h烧结处理后,W-Re合金致密度、显微硬度、抗拉强度、压缩强度及屈服强度分别增加至98.6%,529.7 HV_(0.025),384.7 MPa,1466.5 MPa及879.6 MPa。由于Re元素可提高W-Re合金的再结晶温度,有效细化晶粒,显著提高合金的程度及塑性,等离子喷涂成形W-Re合金经真空烧结后可观察到明显的Re效应。
A W-5% (mass fraction) Re composite powder was prepared by the coating method. An experimental Solid Rocket Motor (SRM) was prepared by atmosphere protection plasma spray forming technique. Density ﹑ organizational structure and microhardness ﹑ tensile strength, compressive strength and other properties with the sintering time changes. The results show that the spray-formed part is a typical columnar layered structure with many pores and micro-cracks in the bonded parts. The compactness of the formed part is 87.5%, and its microhardness, tensile strength and compressive strength are 321.8 HV_ (0.025), 57.9 MPa and 390.2 MPa. With the increase of vacuum sintering time from 2 h to 6 h and 8 h, the W-Re alloy is gradually transformed into a granular structure by the directional solidification of the columnar crystal layer structure, resulting in an increase in the density and the mechanical properties. After 8 h sintering, the density, microhardness, tensile strength, compressive strength and yield strength of W-Re alloy increased to 98.6%, 529.7 HV 0.025, 384.7 MPa, 1466.5 MPa and 879.6 MPa, respectively. Re element can improve the recrystallization temperature of W-Re alloy, effectively refine the grains and significantly improve the degree and ductility of the alloy. The Re-effect of W-Re alloy can be observed after vacuum sintering.