Research On Crack Sensitivity And Stress Field Simulation Of Laser Cladding Nickel Base Superalloy

Since the 1950s,nickel base superalloy has been developing rapidly.In order to achieve higher high temperature oxidation resistance and creep resistance,and lower fatigue crack growth rate,it has been a problem that researchers need to overcome.At present,laser cladding,as a new manufacturing method,provides conditions for directional solidification in addition to its hot and cold characteristics In addition to reducing element segregation to a certain extent,it can also be manufactured freely,which provides the possibility for the repair or manufacture of aeroengine single crystal blades.However,at present,there are neither mature laser cladding technology nor matched alloy powder,so the printed samples will have various defects,especially cracks.In order to solve this problem,this paper considers the influence of laser cladding on cracks from two aspects of process and solid solution elements,hoping to find out a solid solution element composition and process method suitable for Laser Cladding Nickel base single crystal superalloy.The main contents of this paper include:(1)A feasible test scheme is designed.Through the design of substrate and powder,several main solid solution elements in single crystal nickel base superalloy are compared,and their effects on crack sensitivity are analyzed.(2)By analyzing the physical properties of the designed components,such as thermophysical properties,flow stress and so on,the material database of each component is established,and the reference data of these component samples are established,so as to further simulate the temperature field stress field in laser cladding by the finite element software.Through simulation,we can observe the mutual influence of each physical field in the process of cladding,and change different process parameters to obtain the stress field data under different process parameters.By comparing the data,we can choose a more reasonable test process,which not only solves the process problems,but also provides a scientific scheme for the test of the sensitivity of the first designed solid solution elements to cracks and reduces the process parameters The influence of number on crack sensitivity.(3)Through the simulation of temperature field and stress field of each component sample,the influence of each solid solution element on the stress during cladding is counted,and the strength of each component sample is calculated.The influence of solid solution element on the material strength and the stress during cladding are considered comprehensively.Combined with the total crack length counted by each component sample,the three factors are discussed and their correlation process is analyzed Degree,to establish the relationship between the three map.