内燃机用激光增材Ti600合金缺陷表征及其疲劳行为分析  

Characterization of Defects and Fatigue Behavior of Ti600 Alloy Rod Synthesized by Selective Laser Melting

作　　者：石鑫 韩志荣 蒋凡伟 Shi Xin;Han Zhirong;Jiang Fanwei(College of Aeronautical Engineering,Jiangsu Vocational College of Aeronautical Technology,Zhenjiang 212134,China;School of Mechanical Engineering,Guiyang University,Guiyang 550005,China;Guangdong Heavy Industry Construction Supervision Co.,LTD.,Guangzhou 510670,China)

机构地区：[1]江苏航空职业技术学院航空工程学院,镇江212134 [2]贵阳学院机械工程学院,贵阳550005 [3]广东重工建设监理有限公司,广州510670

出　　处：《真空科学与技术学报》2020年第12期1162-1165,共4页Chinese Journal of Vacuum Science and Technology

基　　金：教育部新工科研究与实践项目(20190205103)。

摘　　要：通过准原位疲劳方法测试了选择性激光熔化(SLM)成形态Ti600合金的抗疲劳特性,对合金疲劳损伤机制与裂纹的变化特征进行研究,分析疲劳断口中形成的裂纹尺寸与分布形态。研究结果表明:直径在50μm以内的缺陷频率达到86%,大部分介于12~35μm范围内。缺陷球度频率符合正态分布,缺陷球度低于0.9,基本都介于0.4~0.64范围内。当等效直径逐渐提高后,表现出更大分散性。Ti600合金高周疲劳产生了三个不同的组织区域,包括裂纹源、裂纹扩展与断裂区共三类,疲劳裂都是从试样的表面区域开始萌生,再扩展为半椭圆的外形,形成了平整的断口组织。以SLM成形方法制得的Ti600合金缺陷球度基本都小于0.65,表现出明显的扁平度,同时形成了较大的缺陷与复杂的几何外形。缺陷断口微观结构主要形成了气孔与未熔两种缺陷类型。A rod(Φ20 mm×80 mm)of Ti600 alloy,an advanced material of aircraft internal combustion engine,was synthesized by selective laser melting of constituent powders in argon atmosphere.The fatigue behavior,microstructures/distributions/growth of cracks at fatigue fractures were characterized with scanning electron microscopy and quasi-in-situ fatigue test and numerical calculation.The preliminary results show that when it comes to defects smaller than 50μm and most distributing in 12~35μm range,the defect frequency was 86%;and that the normally distributed defect-sphericity was lower than 0.95,basically in 0.4~0.64 range,and its dispersion increased with an increasing equivalent diameter.In high-cycle-fatigue(HCF)test,three well-defined microstructures,including the crack-source,propagation of surface crack,and flat semi-elliptical fracture,were observed.Moreover,fairly large pores and non-fused powders were found to dominate the fractured surfaces.

关 键 词：激光增材制造 TI600合金 缺陷表征 高周疲劳 

分 类 号：TG146.2[一般工业技术—材料科学与工程]