激光沉积TC4/TC11梯度复合结构各梯度层性能研究

Properties of Gradient Layers of Laser Deposited TC4/TC11 Gradient Composite Structure

采用激光沉积制造技术制备具有3层梯度层的TC4/TC11双钛合金梯度复合结构,研究了TC11含量对各梯度层组织与性能的影响,利用O-LYMPUS光学显微镜(OM)、HVS-1000A型显微硬度计、HT-1000型摩擦磨损试验机、MTS-810疲劳试验机对各梯度层进行微观组织观察、显微硬度测试、室温耐磨性能以及疲劳性能分析。结果表明,各梯度层的显微组织均为典型的网篮组织,粗大的α片层逐渐减少,针状α片层逐渐增多,使梯度材料逐渐均匀地从TC4侧过渡到TC11侧;细小的显微组织不易发生位错滑移,各梯度层随着TC11含量的增加,硬度、耐磨性能和疲劳性能不断提高。25%TC4层的性能最好,其硬度和摩擦系数分别为HV 542,0.42,相对100%TC4层的硬度提高了9.7%、摩擦系数降低了30%,磨损机制主要为粘着磨损和磨粒磨损,25%TC4层在最大应力550和800 MPa下的中值疲劳寿命最高,相对75%TC4层分别提高了21.2%,46.6%。本研究为获得性能较佳的TC4/TC11梯度结构提供参考依据。

The TC4/TC11 dual titanium alloy gradient composite structure with three gradient layers was produced by laser deposition manufacturing technology.The influence of TC11 content on the microstructure and properties of each gradient layer was studied.OLYMPUS optical microscope(OM),HVS-1000 A microhardness tester,HT-1000 friction and wear tester and MTS-810 fatigue tester were used for the microstructure observation,microhardness testing,room temperature abrasion results and fatigue properties analyses of each gradient layer,respectively.The results indicated that the microstructure of each gradient layer was typical basket structure.The coarseαgradually decreased,while the acicularαgradually increased with the increase of TC11 content,so that the gradient material varied gradually and uniformly from the TC4 side to the TC11 side,and fine microstructure impeded dislocation slip.The hardness,wear resistance and fatigue properties of each gradient layer were improved continuously with the increase of TC11 content.The25%TC4 layer had the best performance,and its hardness and friction coefficient were HV 542 and 0.42,respectively.The hardness increased by 9.7%and the friction coefficient decreased by 30%compared with 100%TC4 layer.Wear mechanism were mainly adhesive wear and abrasive wear.The median fatigue lives of the 25%TC4 layer at the maximum stresses of 550 and 800 MPa were the highest,which increased by 21.2%and 46.6%respectively compared with the 75%TC4 layer.This study provided a reference for obtaining better TC4/TC11 gradient structure.