激光冲击强化提高压气机叶片疲劳性能研究

Laser shock peening on vibration fatigue behavior of compressor blade

根据1Cr11Ni2W2MoV不锈钢材料性能,确定了激光冲击强化参数;并通过标准试片疲劳试验,验证了该参数条件下激光冲击强化提高不锈钢材料振动疲劳寿命的有效性.设计了不锈钢叶片振动疲劳试验,确定了叶片冲击强化部位和方式,对强化叶片进行了型面检查、一阶弯曲振动疲劳试验和强化机理研究.结果表明:激光冲击强化后的叶片各个截面尺寸在设计范围之内,强化后叶片的应力-循环次数(S-N)曲线往上移动,提高了叶片的疲劳强度,在660 MPa应力水平下,叶片的振动中值疲劳寿命提高70%;激光冲击强化引起的残余应力和表层微观组织变化是疲劳强度提高的主要原因.

According to the mechanical performance of the 1Cr11Ni2W2MoV stainless steel, the technical parameters of laser shock peening （LSP） were determined. The standard coupons with/without LSP were tested for examining the fatigue performance. It proves that LSP, with the selected parameters, can improve the stainless steel＇s vibration fatigue life remarkably. From the experiment results of coupons, the vibration fatigue experiment for the compressor blade in one certain aero-engine was designed according to the structure and loads of the blade. The treated zone was designed on the surface where the vibration stress is the most severe. In order to avoid macroscopical deformation, the blades were treated on both sides simultaneously. This confirms that different section parameters after LSP on the blade are within the range of design requests. The vibration fatigue results indicate that the S-N （stress-number of cycles） curve with LSP moves up as compared with that one without LSP. When the max vibratory stress was about 660MPa, the blade fatigue life with LSP was pro longed for 70 %. Finally, the reasons were analyzed from the residual compressive stress and micro structure after LSP.