热等静压对等离子喷涂成形制备钼制品的影响

Molybdenum products produced by plasma spray forming and hot-isostatic pressing

先采用球磨加喷雾干燥制备喷涂钼粉,然后通过等离子喷涂制备预设厚度的钼沉积层,再对其进行热等静压处理制备钼制品。使用阿基米德法测量钼沉积层和钼制品的相对密度,用显微硬度计测量它们的维氏硬度,用万能材料试验机测试它们的拉伸强度,用扫描电镜观察它们的外表面、截面和断口微观形貌。研究结果表明:采用等离子喷涂技术能制备致密度达89.7%、拉伸强度达44 MPa、显微硬度(HV)约152、厚度达5 mm的钼沉积层。钼沉积层经过低压热等静压处理后,其显微结构得到改善,相对密度达92%,力学性能提高(拉伸强度达到54 MPa,显微硬度(HV)约246);经二次高压热等静压处理后,钼沉积层的层状结构特征完全消失,颗粒结合紧密,出现等轴晶粒,伴随晶粒长大,断口出现穿晶解理断裂,相对密度达到97.3%,拉伸强度提高到110 MPa,显微硬度(HV)达到321。

Molybdenum feedstock for plasma spraying was fabricated by mechanical alloying and spray drying.Molybdenum products were produced by plasma spray forming（PSF） followed by hot-isostatic pressing（HIP）.The relative density,micro-hardness and tensile strength of Mo products were investigated.Microstructures of surface,cross section and fracture of these products before and after HIP were observed by scanning electron microscope（SEM）.The results show that the relative density,tensile strength and micro-hardness of PSF products increase from 89.7%,44 MPa and 152 to 97.3%,110 MPa and 321,after two-step hot-isostatic pressing,respectively.