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以等离子旋转电极法制备60~200μm粒径的Ti6Al4V合金粉末为材料,研究了两种热等静压工艺(HIP)对Ti6Al4V合金室温拉伸性能与疲劳性能的影响。结果表明:在同时升温升压和先升温后升压HIP工艺下,Ti6Al4V合金的室温拉伸性能相当,抗拉强度σb分别为970和980 MPa,屈服强度σ0.2分别为876和880 MPa,断后延伸率δ分别为9.1%和10.0%;与同时升温升压HIP工艺相比,先升温后升压HIP工艺可明显改善合金的疲劳性能,疲劳极限分别为350和450 MPa。微观组织分析得出:同时升温升压粉末致密化过程中,粉末颗粒的靠近和重排先于颗粒的塑性变形,原始颗粒边界呈较规则空间多边形结构,没有大的变形和破碎,并且颗粒表面杂质元素扩散不充分;先升温后升压粉末致密化过程中,粉末颗粒靠近和重排与颗粒的塑性变形同时发生,原始颗粒边界发生大的塑性变形而被破碎,颗粒之间存在相互插入与包裹,颗粒表面杂质和偏析元素扩散充分,因而先升温后升压HIP工艺后微观组织较粗大,但有更好的疲劳性能。
The effects of two kinds of hot isostatic pressing (HIP) on the tensile properties and fatigue properties of Ti6Al4V alloy at room temperature were studied by using plasma rotating electrode method to prepare Ti6Al4V alloy powder with particle size of 60 ~ 200μm. The results show that the tensile properties of Ti6Al4V alloy are quite similar at room temperature and elevated pressure at the same time and then at elevated temperature. The tensile strength σb is 970 and 980 MPa, the yield strength σ0.2 is 876 and 880 MPa, The elongation at break δ was 9.1% and 10.0%, respectively. Compared with the HIP process, the HIP process could improve the fatigue performance of the alloy at 350 ℃ and 450 MPa, respectively. The results of the microstructure analysis show that during the process of densification of the powder, the powder particle approaching and rearrangement precedes the plastic deformation of the particle, the original particle boundary is in a regular polygonal structure with no large deformation and breakage, and the particle surface In the process of densification of the pressure-boosting powder, the powder particles near and rearranged simultaneously with the plastic deformation of the particles, the plastic deformation of the original particles occurs and is broken, the particles are interpenetrated with each other and The inclusions and segregation of particles on the surface of the particles are well diffused. Therefore, the micro-structure is coarser after the first heat-up and post-pressure-boosting HIP process, but has better fatigue properties.