粉末冶金Nb-35Ti-6Al-5Cr-8V合金组织演变及其力学行为

采用粉末冶金法对不同球磨时间的Nb-35Ti-6Al-5Cr-8V合金机械合金化粉末塑变行为，热压烧结材料的微观组织结构和力学行为进行了研究。研究结果表明：塑性良好的Nb-35Ti-6Al-5Cr-8V粉末随着球磨时间增加首先变形为大尺寸的片状、后经持续的加工硬化破碎成絮状；热压烧结能够制备微观组织可控晶粒细化的Nb-35Ti-6Al-5Cr-8V合金，合金由单一的Nbss相构成，Ti、Al、Cr、V元素固溶引起Nb晶格尺寸减小0.0685 ?；随着球磨时间增加合金晶粒明显细化进而显著提高了合金的维氏硬度和室温压缩强度，其变化符合材料硬度和强度的Hall-Petch规律。粉末冶金制备Nb-35Ti-6Al-5Cr-8V合金的各项力学性能明显优于熔铸法制备合金。

Microstructure Evolution and Mechanical Behavior of Powder Metallurgy Nb-35Ti-6Al-5Cr-8V Alloy

The plastic deformation behavior of mechanical alloying powder at different ball milling times, microstructure and mechanical properties of hot press sintering Nb-35Ti-6Al-5Cr-8V alloys were investigated using powder metallurgy method. The results show that the Nb-35Ti-6Al-5Cr-8V powders with good plasticity were deformed into large-sized flakes powder firstly, and then broken into flocculent powder during continues process hardening as the increasing of ball milling time. The Nb-35Ti-6Al-5Cr-8V alloy with controllable microstructure and fine grain can be prepared using hot pressing sintering technology, and the sintered materials consist of single Nbss phase. The solid solution element of Ti, Al, Cr and V dissolving into Nb crystal causes the reduction of lattice size about 0.0685 ?. The Vickers hardness and the compression strength at room-temperature were increased significantly for grain refinement caused by ball milling time increasing, and this trend was in accordance with the Hall-Petch law of hardness and strength for material. It can be firmed that multi-mechanical properties of Nb-35Ti-6Al-5Cr-8V alloy prepared by powder metallurgy technology are obviously better than these prepared by fusion casting method.