无保护层激光冲击强化提高K24镍基合金疲劳强度试验研究（英文）  

Experiment Study on Improving Fatigue Strength of K24 Nickel Based Alloy by Laser Shock Processing without Coating

作　　者：罗思海[1] 聂祥樊[1] 王学德[1] 王波[1] 李靖[1] 何卫锋[1] 

机构地区：[1]空军工程大学等离子体重点实验室,陕西西安710038

出　　处：《稀有金属材料与工程》2017年第12期3682-3687,共6页Rare Metal Materials and Engineering

基　　金：National Basic Research Program of China(2015CB057400);National Natural Science Foundation of China(51405506,51505496)

摘　　要：通过采用无保护层激光冲击强化提高K24镍基合金的抗疲劳特性。首先,采用高周振动疲劳试验验证了无保护层激光冲击强化效果,疲劳试验结果表明,强化后K24镍基合金疲劳强度相比于未强化试件的282 MPa提高到328 MPa。其次,通过采用扫描电镜(SEM)观察、残余应力和显微硬度测试研究了多次冲击对K24镍基合金机械性能以及断口形貌的影响。残余应力测试结果表明,无保护层激光冲击强化后表面形成了压应力,表面最大达到–595 MPa,且影响深度为150μm。同样3次冲击后表面显微硬度(HV0.5)增加到5260 MPa,深度约为100μm。断口形貌特征表明强化后裂纹源区更加平坦,同时裂纹扩展速率降低。最后,基于疲劳试验和力学性能测试结果进一步讨论了激光冲击强化提高疲劳强度的影响机制。Laser shock processing without coating（LSPw C） was used to improve the fatigue resistance of K24 nickel based alloy.Firstly,high cycle vibration fatigue experiment was adopted to verify the LSPw C strengthening effect.Compared to the untreated samples,the results of the vibration fatigue experiments show that the fatigue strength of K24 alloy is enhanced and improved from 282 MPa to 328 MPa after LSPw C.Secondly,the effects of multiple impacts on mechanical properties and fatigue fracture morphologies were investigated,which were observed and measured by scan electron microscope（SEM）,X-ray diffractometer and microhardness tester.The results indicate that the residual stress presents compressive state on the superficial layer with about 150 μm depth and the maximum value reaches –595 MPa.The microhardness（HV0.5） is about 5260 MPa with about 100 μm depth from the top surface after three impacts.The fracture observation indicates that the flatness area is larger in the fatigue crack initiation（FCI） after LSPw C;meanwhile,the growth rate of fatigue crack is decreased.Lastly,the strengthening mechanism of LSPw C on the fatigue resistance was discussed based on the experimental results.

关 键 词：无保护层激光冲击强化 K24镍基合金 高周疲劳 疲劳断口 残余应力 强化机制 

分 类 号：TG146.15[一般工业技术—材料科学与工程]