(1. 华南理工大学 国家金属材料近净成形工程技术研究中心，广州 510641；
2. 华南理工大学 金属材料高效近净成形技术与装备教育部重点实验室，广州 510640)
摘 要: 利用放电等离子烧结(SPS)技术对具有相同理论密度的烧结态93W-4.9Ni-2.1Fe和95W-2.8Ni-1.2Fe-1Al2O3高密度钨合金进行循环热处理，并通过光学显微镜、SEM、TEM、EDS和三点弯曲实验分析循环热处理对两种合金显微组织和力学性能的影响规律。结果表明：随着SPS循环热处理次数的增加，93W-4.9Ni-2.1Fe合金在平均W晶粒尺寸未发生明显变化的同时，其粘结相中的W含量和位错密度不断升高，合金得到了固溶强化与位错强化，合金的硬度、抗弯强度、断裂挠度等性能相应提高；而对于95W-2.8Ni-1.2Fe-1Al2O3合金，由于更高的W含量和Al2O3颗粒的加入，烧结态时具有小得多的平均W晶粒尺寸、更大的W-W连接度和高硬脆特性，且SPS循环热处理对其组织和成分分布的均匀性影响程度相对较小，其力学性能虽然随SPS循环热处理次数的增加也得到了一定程度改善，抗弯强度和断裂挠度明显较93W-4.9Ni-2.1Fe合金的低，硬度则明显高于93W-4.9Ni-2.1Fe合金硬度。但循环热处理次数过多，反而会降低两种钨合金的硬度和断裂挠度。
关键字: 高密度钨合金；放电等离子烧结；循环热处理；组织；性能
（1. National Engineering Research Center of Near-Net-Shape Forming for Metallic Materials, South China University of Technology, Guangzhou 510641, China;
2. Key Laboratory of High-efficiency Near-net-shape Forming Technology and Equipments for Metallic Materials, Ministry of Education, South China University of Technology, Guangzhou 510640, China）
Abstract:The effect of cyclic heat-treatment based on spark plasma sintering (SPS) technique on the microstructure and mechanical properties of as-sintered 93W-4.9Ni-2.1Fe and 95W-2.8Ni-1.2Fe-1Al2O3 heavy alloy with the same theoretical density was studied by optical microscopy, SEM, TEM, EDS and three –point bending tests. The results show that with increasing the SPS cycle index, the average W grain size of 93W-4.9Ni-2.1Fe alloy unchanges markedly, while both the tungsten content and dislocation density in matrix tend to increase. As a result, the hardness, bending strength and fracture deflection of the alloy are improved gradually owing to solid solution and dislocation strengthening by the treatment. 95W-2.8Ni-1.2Fe-1Al2O3 alloy, possesses quite less average W grain size, higher W-W contiguity and highly hard and brittle characteristics, because of the higher W content and the addition of Al2O3 particles. Its microstructure and composition distribution are affected in a lower degree by SPS cyclic heat-treatment. Although the mechanical property is improved with increasing the SPS cycle index, the obtained bending strength and fracture deflection are obviously lower those of 93W-4.9Ni-2.1Fe alloy, except quite bigger hardness. However, too many times of cyclic heat treatment induce the decrease of hardness and fracture deflection of the two types of alloys.
Key words: tungsten heavy alloy; spark plasma sintering; cyclic heat-treatment; microstructure; property
