摘要
对TC11钛合金进行激光冲击强化处理,通过透射电子显微镜观察不同参数下TC11钛合金的微观组织变化,用显微硬度计和X射线应力测试仪分别测试材料表层硬度和残余应力,并通过TC11钛合金标准疲劳试片高周振动疲劳试验验证激光冲击对其疲劳性能的影响.试验结果表明:激光冲击波作用后表面组织结构发生明显变化,当冲击次数增加,先后出现了高密度位错、位错胞和纳米级晶粒等微观组织特征.冲击10次后,表面残余应力最高达到-632.5MPa,相应的塑性变形层深度达到1500μm左右;同时表面硬度在冲击1次即可提高19%,硬度影响深度为700μm,随着次数增加而提高,但幅度不大.经3次冲击处理的TC11钛合金标准疲劳试片的疲劳极限由原始483MPa提高到593MPa.
TC11 titanium alloy was treated by laser shock peening （LSP）, while micro- structure, residual stress and microhardness without/with LSP in different laser impacts were examined and compared via transmission electron microscope （TEM）, X-ray diffractometer and microhardness tester. The high-cycle vibration fatigue test of TC11 titanium al- loy standard vibration specimens was conducted to verify effects of LSP on the high-cycle fa- tigue property. The results indicated that severe plastic deformation was formed and grains on the surface were refined with high-density dislocations, dislocation ceils. Nanocrystals were generated successively with increasing laser impact. The maximum residual stress reached --632.5MPa in 10 impacts with 1 500μm thick plastic deformation layer. The micro- hardness was increased by 19% with 700μm thick affected layer. The affected depth increased with the laser impact, but amplitude was limited. Fatigue limit of TCll titanium alloy standard vi- bration specimens treated by LSP in 3 impacts had been improved from 483 MPa to 593 MPa.
出处
《航空动力学报》
EI
CAS
CSCD
北大核心
2014年第2期321-327,共7页
Journal of Aerospace Power
基金
国家自然科学基金(51205406)
西安市科技计划项目(CXY116(4))
