Numerical Study On Laser Surface Treatment Considering Properties Of Cladding Layer

Pure copper is widely used in many scientific fields because of its excellent conductivity and thermal conductivity,However,the defects of low hardness and poor strength will restrict its further application.therefore,it is of great significance to add other metal elements on the surface of pure copper and improve its properties by surface modification technology.In view of the infinite mutual solubility of copper and nickel and the characteristics of high energy density and sudden temperature rise and drop of laser cladding,it can settle the problem with advantage.nevertheless,the temperature and residual stress in the course of laser cladding have great influence on the machinability,In order to study the temperature and residual stress distribution of cladding layer and substrate in multi-layer and multi-channel laser cladding and the influence of nickel content on the performance of cladding layer,in this article,pure copper matrix,copper nickel alloy cladding layer as ob Ject of study,carried out three dimensional transient finite element numerical emulation,the main contents and conclusions are as below:Using orthogonal test method to qualitative research the influence of laser parameters and preheat temperature on temperature realm and stress realm in multi-layer single pass cladding and determine the optimum laser power,scanning speed and spot radius,the temperature and the residual stress on the surface of the basal body are in proportion to the laser power and inversely ratio to the scanning speed and spot radius,within a reasonable preheating temperature limits,the higher the preheating temperature is,the smaller the residual stress is.Based on the optimized parameters,the temperature realm and stress realm distribution of Cu Ni alloy are simulated and analyzed according to three different laser scanning paths,the results show: in multi-layer and multi-channel scanning,the latter one has obvious preheating effect on the former one;the scanning path mainly affects the residual stress parallel to the scanning direction;When using reverse lateral scanning,the residual stress at the interface between cladding layer and basal body is more equality,it is the best scanning path.Analyzed the influence of different nickel content on the properties of Cu Ni alloy,and research the deformation and residual stress of multi-layer and multi-channel cladding by comparison: The nickel content is directly proportional to the elastic modulus,hardness and strength,is inversely proportional to thermal conductivity and electrical conductivity;but there is no qualitative relationship with residual stress.