摘要
高周疲劳是航空发动机部件的主要故障之一。通过对1Cr11Ni2W2MoV不锈钢进行不同次数的激光冲击强化(LSP)处理,研究冲击次数对激光冲击强化材料高周疲劳性能的影响。对不同处理状态的试件进行常温振动疲劳试验,采用X射线衍射(XRD)应力分析仪、扫描电镜(SEM)、金相显微镜等手段研究冲击次数对材料组织和力学性能的影响。试验结果表明,随着LSP冲击次数的增加,1Cr11Ni2W2MoV不锈钢表面粗糙度增大,组织细化层厚度没有变化,残余应力梯度变小,残余压应力层深度增加,1次冲击后,残余压应力层深为1.8mm,3次冲击后为2.5mm。表面残余压应力随着冲击次数增加而逐渐趋于饱和,饱和值接近于-100%σ0.2。振动疲劳试验结果表明,疲劳寿命随着LSP次数增加而提高,但提高幅度减小。在σmax=640MPa应力水平下,1次冲击后试样疲劳寿命是未强化试样的3.8倍,3次冲击后试样疲劳寿命是未强化试样的5倍。经分析,多次冲击时的冲击波叠加效应使得冲击波传播到材料的更深层,从而使材料组织变形层和残余应力影响层更深,高周疲劳寿命提高更大。
High cycle fatigue is one of the main failures of aero-engine. The improvement of HCF properties by laser shock processing （LSP） with multiple impacts is researched. Vibration fatigue tests of different 1Cr11Ni2W2MoV stainless steel samples are conducted at room temperature. X-ray diffractometry （XRD）, scanning electron microscopy （SEM） and metallography microscope are used to investigate the influence on microstructure and mechanical performances with different impacts. The results show that with the laser impact times increasing, the residual stress and the roughness increase, while the depth of microstructure refining layer doesn′t change. The surface compressive residual stress is driven to saturation and the saturation value is up to -100%σ0.2. The depth of compressive stress has a wider increase with the impact times increaseing. Vibration tests show that the fatigue properties improve with the impact times increasing. By the superimposed effect of shock waves in multi-impact processing, the shock wave can translate into deeper materials, which make a great contribution to the greater depth of compressive residual stress and deformation microstructure, and to the further improvement of fatigue properties with multiple impacts at room temperature.
出处
《中国激光》
EI
CAS
CSCD
北大核心
2014年第1期46-51,共6页
Chinese Journal of Lasers
基金
国家自然科学基金(51205406)
