一种通过改变激光功率密度分布控制熔覆层裂纹的方法  

A Method of Crack Control in Laser Cladding Process with Changing Power Density Distribution of Laser Beam

作　　者：王东生[1,2] 田宗军[2] 王泾文[1] 段宗银[1] 沈理达[2] 黄因慧[2] 

机构地区：[1]铜陵学院机械工程系,安徽铜陵244000 [2]南京航空航天大学机电学院,江苏南京210016

出　　处：《中国激光》2011年第1期76-80,共5页Chinese Journal of Lasers

基　　金：国家自然科学基金(59975046;50305010);江苏省自然科学基金(BK2004005;BK2009375);铜陵学院引进人才科研启动基金资助课题

摘　　要：为了降低激光熔覆过程中熔覆层热应力从而减少裂纹的生成,提出了一种通过改变激光功率密度分布来控制熔覆层裂纹的方法,并用数值模拟的方法对均布及凸字形光斑熔覆过程进行了热力耦合有限元分析。结果表明,用均布光斑熔覆呈现出激光加工典型的快速加热、快速冷却特征,而采用凸字形光斑可在一定程度上起到预热、缓冷的效果,从而降低了熔覆区与非熔覆区的温度梯度,另外,在熔覆效果相当的前提下,其熔覆层热应力也较小,因而可以有效地减小熔覆层的开裂趋势。In order to reduce thermal stress and crack of clad layer in laser cladding process, a method through changing power density distribution of laser beam was presented. A thermal-mechanical coupling finite element model of laser cladding by using uniform shape and convex shape laser spot was established. The results show that laser cladding with uniform shape spot has a typical character of quick heating and cooling rate as the conventional laser manufacturing. However, laser cladding with convex shape beam could preheat and slow cooling rate of sample to some extent, and reduce the temperature gradient between the clad area and non-clad zone. In addition, the thermal stress of clad layer with convex shape laser beam is lower than the uniform shape laser spot dose, so it can effectively reduce crack of the clad layer.

关 键 词：激光技术 激光熔覆 熔覆层裂纹 控制方法 热应力 

分 类 号：TN249[电子电信—物理电子学] TG156.99[金属学及工艺—热处理]