Study On Property Of Laser Deposition Manufacturing TC4 Titanium Alloy

Titanium alloy is characterized by high specific strength,high thermal strength,corrosion resistance,low density,low thermal conductivity,good weld-ability and good biocompatibility It is a lightweight,high-strength and corrosion resistant structural material,and has wide application prospects.LDM combines laser,computer controlling technology,Computer Numerical Control and machine and other advanced technologies,which can manufacture high performance and complex structure components in short time.The properies of several typical small and medium size parts made by LDM are comparable to the forgings in present,and the Manufacturing capacity of large-scale parts has also made a breakthrough.TC4 titanium alloys are widely used,it's structure and mechanical properties are also relatively stable,and the alloying is simple,TC4 titanium alloys are mainly used to produce aircraft engines and some important load-bearing structures.For a long time,the forming process of TC4 titanium alloy structure used in aerospace field is mainly forging.The application and research of LDM TC4 titanium alloy are less.In this study,the mechanical properties of laser deposition manufacturing of TC4 titanium alloy were discussed,such as microstructure,fracture morphology,microhardness,impact property at room temperature and tensile properties at room temperature and high temperature.The research shown that:It can be seen that there exhibits a continuously epitaxial columnar ? cellular growth across several deposit layer,whose growth direction is along the deposited direction and inclines towards the scanning direction in some sort.The as-deposited microstructures were composed of acicular ? and Widmanstatten ? in prior ? grain.Due to the LDM microstructures distribute inhomogeneous,leading to the anisotropy of mechanical properties.The microhardness of LDM TC4 samples vary greatly in different direction.The microhardness of deposition direction is lower than scanning direction.What`s more,there is a correlation between microhardness and the percentage composition of ?.The value of microhardness changes with the percentage composition of ?.The impact property at room temperature of LDM TC4 samples in deposition direction and scanning direction is different.The impact property in deposition direction is higher than scanning direction,and after stress relief annealing,the impact property has increase.The fracture mode is ductile fracture in deposition direction and brittle fracture in scanning direction.The tensile properties and fracture morphology of TC4 titanium alloy were investigated by laser deposition of local.The results show that the tensile strength of deposition direction is lower than the vertical deposition direction,but the plastic is much higher than the latter.Compared with tensile properties at high temperature and room temperature,the tensile strenght decline and elongation and reduction of area improve in both direction.