温度辅助的激光冲击技术研究进展

Research Progress of Temperature-Assisted Laser Shock Technology

温度辅助的激光冲击技术是在激光冲击技术上发展而来的结合热力耦合效应的高能率加工和表面处理技术。在介绍温度辅助的激光冲击技术原理和特点的基础上,分析了激光冲击波的压力模型及时空分布特性、温热及高应变率下材料的本构模型,重点介绍了利用温度辅助的激光冲击效应的两项技术——温度辅助激光微成形和激光温喷丸强化。温度辅助激光微成形技术作为一种新颖的高能率微细加工技术,其在温热条件下利用脉冲激光诱导的冲击波压力使金属箔板塑性成形微结构件,可使激光冲击微拉深件的塑性变形均匀性得到显著改善,成形高度较室温下得到进一步提升。激光温喷丸强化技术作为新形材料表面处理工艺,结合了热力耦合效应在应力强化和组织强化方面的诸多优势,能够获得比常温激光冲击强化技术更稳定的残余压应力分布,有效提高材料的耐热腐蚀性和疲劳性能。综述了温度辅助激光微成形和激光温喷丸强化技术的研究现状,指出了当前在温度辅助的激光冲击技术研究中存在的问题,并对今后的研究做了展望。

The temperature-assisted laser shock technology developed from the laser shock technology is a high-energy processing and surface treatment technology, which combines thermal mechanical coupling effects. Based on the introduction of working principle and features of the temperature-assisted laser shock technology, the pressure model and time-space distribution characters of laser shock wave and constitutive model of materials under tepidity and high strain rate were analyzed. Two techniques utilizing the temperature-assisted laser shock effects： temperature-assisted micro scale laser shock forming and warm laser peening were mainly introduced. The temperature-assisted micro scale laser shock forming technique was a novel mi-cro-processing technique of high energy rate. Under warm conditions, it could make micro structure of metal foil sheet plastic-formed by means of shock-wave pressure induced by the pulse laser and remarkably improve plastic deformation uniformity of micro deep-drawn parts. The forming height was further improved compared with that at room temperature. As a new surface treatment technology for the materials, the warm laser peening technology combining the advantages of thermal mechanical coupling effect in stress strengthening and structure strengthening could obtain the residual compressive stress distribution more stable than that of laser shock processing technology obtained at room temperature. In such case, the thermal corrosion resistance and fatigue properties of materials could be also improved effectively. After summarizing the research status about the temperature-assisted micro scale laser shock forming technology and the warm laser peening technology, the problems existing in current research of the temperature-assisted laser shock processing are pointed out. Finally, expectations of future studies on the technology are brought forward.