三种不同粒径分布的Ti-6Al-4VELI球形粉末热等静压件的显微组织及力学性能

Microstructure and mechanical properties of Hot Isostatically Pressed with three different diameter distributions of Ti-6Al-4VELI alloy spherical powders

摘要:

我们研究了经等离子旋转电极法制备的三种不同粒径分布的Ti-6Al-4VELI(低间隙)合金球形粉末经热等静压工艺制件后的显微组织和力学性能。Ti-6Al-4VELI合金球形粉末经940℃及120MPa同时升温升压的热等静压工艺制件。利用光学显微镜(OM),扫描电子显微镜(SEM)及能谱仪(EDS)可观察到HIP制件中的α+β混合相。研究结果表明,Ti-6Al-4VELI合金球形粉末经热等静压制件后的显微组织与粉末粒径分布有很大关系。与Ti-6Al-4VELI合金中粉(粒径分布范围：100μm~150μm)及粗粉(粒径分布范围：150μm~250μm)制成的热等静压件相比,由Ti-6Al-4VELI合金细粉(粒径分布范围：45μm~100μm)制成的热等静压件呈现出更为优异的显微组织及力学性能,表现为更为细化的显微组织和更高的抗拉强度及延伸率,与粉末热等静压制件的显微断口分析结果相一致。

Abstract:

We report the microstructural and mechanical analysis of Ti-6Al-4VELI (Extra Low Interstitial) alloy parts fabricated with three diameter distributions of Ti-6Al-4VELI spherical powders by Hot Isostatic Pressing (HIP), which were manufactured via plasma rotating electrode processing (PREP). The powders were canned and pressed at temperatures 940℃ and pressure 120MPa. Alpha-beta mixed phases in the specimens were observed through Optical Microscope (OM), Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) methods, respectively. The results show the microstructures of specimens were found to be strongly dependent on the different distributions of powders. The samples formed from fine powders (particle size range from 45μm to 100μm) shows better microstructure properties to those formed from medium powders (particle size range from 100μm to 150μm) and coarse powders (particle size range from 150μm to 250μm). In addition, the billets formed from fine powders exhibited higher tensile strength and ductility than those formed via medium powders and coarse powders. These results were attributed to the initial microstructures of HIP samples, as confirmed by evaluating their fracture features