CAJ | 학술논문

对K4030镍基高温合金涡轮叶片进行了激光冲击强化，研究了激光冲击诱导残余应力场分布、激光冲击引起的表层硬化以及在350℃、500℃和550℃保温下的热稳定性。实验结果表明：激光1次冲击在表层诱导了-625 MPa的残余压应力，影响深度大于1 mm，冲击次数越大，残余应力幅值和影响深度愈大；功率密度和冲击次数显微硬度有较大影响，激光冲击强化后，其显微硬度有大幅度提升，并形成了一定厚度的变形层，增加冲击次数或者增大功率密度都可提高其幅值，在550℃/60 min保温下，残余应力大部分松弛，但是激光冲击强化引起的表层硬化即诱导的微观组织变化具有良好的热稳定性。激光冲击强化提高涡轮叶片高温高低周疲劳寿命达2．4倍。激光冲击强化诱导的残余压应力和晶粒细化是镍基合金疲劳强度提高的主要原因。
대K4030얼기고온합금와륜협편진행료격광충격강화，연구료격광충격유도잔여응력장분포、격광충격인기적표층경화이급재350℃、500℃화550℃보온하적열은정성。실험결과표명：격광1차충격재표층유도료-625 MPa적잔여압응력，영향심도대우1 mm，충격차수월대，잔여응력폭치화영향심도유대；공솔밀도화충격차수현미경도유교대영향，격광충격강화후，기현미경도유대폭도제승，병형성료일정후도적변형층，증가충격차수혹자증대공솔밀도도가제고기폭치，재550℃/60 min보온하，잔여응력대부분송이，단시격광충격강화인기적표층경화즉유도적미관조직변화구유량호적열은정성。격광충격강화제고와륜협편고온고저주피로수명체2．4배。격광충격강화유도적잔여압응력화정립세화시얼기합금피로강도제고적주요원인。
The laser shock processing (LSP)was carried out for turbine blades of K4030 nickel-based alloy.Both the residual compressive stress distribution and case-hardening were researched in the specimens before and after LSP treatment,and the residual stress relaxation regularity is studied when vacuum thermal retardation was at 300 ℃、500 ℃ and 550 ℃ for 60 min.The results showed that:one laser shock induced residual compressive stress of-625 MPa at the surface,the impact is greater than the depth of 1 .5 mm,the impact numbers are more,the effect of residual stress amplitude and depth are greater;laser energy and impact numbers have an influence on micro hardness.And mi-cro hardness of K4030 nickel-based alloy has been improved greatly after laser impact,and forms a severe plastic de-formation layer,and increasing impact numbers or laser energy will improve the amplitude and enhance affected depth.But when the K4030 nickel-based alloy after LSP is subjected to heat treatment at 550 ℃/60 min,the most of residual compressive stress has gotten the relaxation,while the micro hardness has still remained good thermal stabili-ty.The high-and-low cycle fatigue tests prove that the fatigue life with LSP is 2.4 times longer than that without LSP under high temperature environment.The refined structure and high compressive residual stress are the main reasons of improving the fatigue performance.