碳纤维复合材料激光加工热损伤问题的研究现状

Research Status of Thermal Damage in Laser Processing of Carbon Fiber Reinforced Plastic

碳纤维复合材料(CFRP)是由碳纤维和基体组成的二相或多相结构,具有非均质和各向异性,且碳纤维的硬度很高,采用传统的机械加工方式易出现如刀具磨损、复合材料分层、纤维破碎及加工后性能变差等问题。使用激光加工可以克服其技术方面所面临的各种困难,但由于CFRP中碳纤维增强体在热膨胀系数、气化温度等热力学性能方面与基体存在相当大差异,激光加工过程中易出现热影响区、纤维拔出、复合材料分层、纤维末端膨胀等热损伤缺陷,严重影响CFRP的静态强度,导致激光加工CFRP面临巨大挑战。综述了国内外降低激光加工碳纤维复合材料的研究现状,通过采用短脉冲、短波长、重复频率高的激光光源,以及提高加工速度、改进加工路径、一定压力的吹气等多种方法降低激光与材料的作用时间,从而减少热效应。

Carbon Fiber Reinforced Plastic(CFRP)is a two-phase or multi-phase structure composed of carbon fiber and matrix,and is heterogeneous and anisotropic.It is a kind of typical difficult-to-machine materials for traditional machining process,and could cause many problems,such as tool wear and composites delamination,fiber breakage and poor performance after processing.The laser processing technology can overcome these problems.But carbon fiber and matrix have obvious differences in material thermodynamic properties,such as thermal expansion coefficient and gasification temperature.During laser processing,thermal damage defects such as heat-affected zone,fiber extraction,layering of composite materials,and fiber end expansion are prone to seriously affect the static strength of CFRP.This paper reviews the state of art of thermal damage reduction in laser processing of CFRP.Thermal effects can be reduced by selecting laser light source with short pulse,short wavelength,high repetition frequency,improving process parameters,such as processing path,blowing pressure.