铝箔防护条件下激光冲击强化产生的表面缺陷研究(英文)  

Surface Defects Produced by Laser Shock Peening with Aluminium Foil Ablative Layer

作　　者：曹子文[1] 巩水利[1] 邹世坤[1] 车志刚[1] 

机构地区：[1]北京航空制造工程研究所高能束流加工技术国防科技重点实验室,北京100024

出　　处：《稀有金属材料与工程》2013年第S2期217-221,共5页Rare Metal Materials and Engineering

基　　金：NSFC(50824001)

摘　　要：利用脉宽30 ns的钕玻璃激光器强化铝箔烧蚀层覆盖的TC17钛合金,激光光斑尺寸为4 mm×4 mm。对强化表面的缺陷进行表面形貌分析、能量色散X射线成份分析(EDX)和扫描电镜分析。在强化表面发现了许多微小的压痕缺陷,在微小压痕内及其附近探测到了碳元素分布。随着激光冲击次数增加,铝箔烧蚀层的厚度逐渐降低,因此在4个方形光斑中心搭接区的铝箔发生微小的破损,但未发现基体材料表面发生烧蚀情况。当铝箔表面较大面积发生破损或者激光直接照射在基体材料表面,将产生厚度为1～3μm的再铸层,并且在再铸层中发现数量众多的微裂纹和气孔。The ablative layer acts as a sacrificial layer to prevent a slight burning of the surface in laser shock peening.Aluminium foil was applied to be ablative layer in almost all of industrial applications,because of its excellent toughness and easy maneuverability.In this experiment,Nd: glass laser system with pulse duration of 30 ns and spot size of 4 mm×4 mm was applied for peening TC17 titanium alloy covered by aluminium foil.Surface defects on peened areas were studied by surface morphology detecting,EDX chemical composition analysis and SEM observation.Some micro impression defects were found on peened areas,and carbon element was detected in and around micro marking defects.Results show that aluminium foil thickness is decreased as increasing impact times,thus a tiny broken surface of aluminium foil is found just at overlapped area by four square spots,and no heat affected layer is observed on substrate surface.In case of relatively large area of aluminium foil damage or laser pulse directly irradiated on base material surface,the thin recast layer with thickness of 1～3 μm is generated,and a number of micro-cracks are found in recast layer and some pores locate at interface between melting layer and original material.

关 键 词：激光冲击强化 表面缺陷 铝箔吸收层 

分 类 号：TG665[金属学及工艺—金属切削加工及机床]