真空热处理对微波烧结93W-Ni-Fe合金显微组织及力学性能的影响

研究真空热处理对微波烧结挤压棒坯93W-Ni-Fe合金显微组织及力学性能的影响,采用高倍SEM和光学金相分别对合金断口和显微组织进行观察,采用能谱分析仪对合金真空热处理前后各元素含量进行定量分析,并对真空热处理样的相对密度、抗拉强度、延伸率和硬度进行测定和分析.结果表明:经真空热处理后,钨合金的各项力学性能都得到了提高,抗拉强度和延伸率提高显著,抗拉强度从920 MPa提高到了988 MPa,延伸率从9.7％提高到了18.6％；真空热处理后,显微组织中钨晶粒的连接度降低,合金断口中钨晶粒的穿晶解理断裂和粘结相的延性撕裂增多;真空热处理后合金粘结相中的钨含量明显降低.

Effects of Vacuum Heat Treatment on Microstructure and Mechanical Properties of 93W-Ni-Fe Alloy by Microwave Sintering

Effects of vacuum heat treatment on microstructure and mechanical properties of extruded rods of 93W-Ni-Fe alloy sintered by microwave were studied. Fracture morphology and microstructure were observed by SEM and optical microscope, respectively. Quantitative analysis of each element of the samples before and after vacuum heat treatment was performed by energy spectrum analyzer. Relative density, tensile strength, elongation and hardness of samples were measured. The results show that the mechanical properties of the tungsten-based alloy are increased after vacuum heat treatment. Tensile strength and elongation are improved markedly, which are increased from 920 MPa to 988 MPa and from 9.7% to 18.6%, respectively. After vacuum heat treatment connectivity of tungsten grains is reduced, and transgranular cleavage fracture of tungsten grains and ductile tearing of binding phase are increased evidently. The content of tungsten element in binding phase is obviously reduced after vacuum heat treatment.