Study On Technology And Properties Of Laser Hybrid Fabricated Based On TA15 Titanium Alloy Forging

In order to achieve high-efficiency and high-quality manufacturing of titanium alloy large integral structural parts,forge+laser deposition manufacturing hybrid fabricated technology is mentioned in this paper.This method refers to laser deposition manufacturing on a forging blank or semi-finished parts to complete a component.In this paper,using TA15titanium alloy powder as raw material,hybride fabricated TA15 titanium alloy specimens were prepared.In order to study the mechanical properties and microstructure of hybrid fabricated TA15 titanium alloy specimens,the microstructure and fracture morphology were analyzed by an optical microscope(OM)and a scanning electron microscope(SEM),and room tensile properties and microhardness were examined.The effect of cyclic heat treatment on tensile properties at room temperature and microstructure was also discussed.The results show that the hybride fabricated specimens consists of three parts:the wrought substrate zone(WSZ),the laser deposition manufacturing zone(LDMZ)and the heat affect zone(HAZ).The microstructure of WSZ is duplex microstructure and LDMZ is columnar priorβgrains in which very fineαlaths compose basketweave.The volume fraction of equiaxialαgrains decrease as approaching LDMZ in HAZ.After cyclic heat treatment,spheroidization of primary equiaxialαgrains occurs in WSZ,the size ofαlamellas in LDMZ coarsens,and the crystallographic orientation of adjacentβcolumnar crystals tends to be the same.The tensile properties of hybride fabricated specimens exhibit significant anisot_—ropy due to the fact that there are differences between Schmid factors of slip systems of{1120}_?and{011~—2}_?texture when loading directions are different.The ultimate tensile strength and yield strength of Z are lower than XY and the plasticity is higher.Cyclic heat treatment can reduce strength and improve plasticity.The microhardness of LDMZ is higher than that of WSZ,and the HAZ is between them.After cyclic heat treatment,the microhardness of WSZ has no obvious change,and the difference of LDMZ is obvious:the annealed state is slightly higher than the deposited state,and the microhardness of samples decrease after cyclic heat treatment,which is mainly due to the different ratio of length to width ofαlamellas.