Microstructure And Properties Of Ti-Zr Alloys Fabricated By Laser Additive Manufacturing

Laser additive manufacturing technology has significant advantages such as highflexibility,short cycle,easy operation,and cost saving,so it has received extensive attention from all sectors of the society and has been rapidly developed.However,at present,the research and development of materials used for this technology are insufficient.The existing materials cannot meet the practical requirements of their applications.Therefore,a material system that can satisfy both the process characteristics of laser additive manufacturing and performance is crucial for material manufacturing technology to achieve engineering production.According to the Ti-Zr binary alloy phase diagram,the Ti-Zr alloy with Zr content of20-60 at.% was selected around the alloy's congruent point(40at.%Zr),and the alloys was prepared on TA2 pure titanium using laser additive manufacturing technology.Then use XRD,SEM,EPMA and EBSD to analyze the microstructure of alloys with different Zr content;and use OLYMPUS laser confocal microscope,microhardness tester,friction and wear tester,universal testing machine and electrochemical workstation test the hardness,friction and wear properties,compression properties and corrosion resistance of different Zr content alloys.The experimental results show that Ti-Zr alloys with different Zr content mainly consist of ?-Ti solid solution and ?-Ti solid solution,and ?-Ti diffraction peak show obvious preferential orientation on the(200)surface with increasing Zr content;Microstructure of the20 at.%Zr alloy is the same as the structure of the basket.With content of Zr continues to increase,the ?-Ti solid solution gradually appears as granular.The total precipitation of ?-Ti and the segregation of columnar grains both decrease first and then increase with increasing Zr content.When the Zr content is 40 at.%,the microstructure of the alloy almost is all columnar ?-Ti solid solution and the composition is the smallest segregation.With the increase of Zr content,the single-clad width of the alloy increases first and then decreases,and the surface roughness first decreases and then increases.The single-clad width of40 at.%Zr alloy is the largest.(2.81mm)and the smallest surface roughness(4.628?m)indicate that the alloy has the highest forming accuracy.In terms of mechanical properties,as the Zr content increases,the hardness of the alloy first decreases and then increases.When the Zr content is 40 at.%,it reaches a minimum value(438.23 HV);under the condition of dry sliding friction and wear,the main wear mechanism for abrasive wear,with the increase of Zrcontent,the friction coefficient and wear volume of the alloys are all increase first and then decrease.The attrition resistance and wear resistance of 40 at.%Zr alloy are the worst;after compression,the alloy both show the characteristics of shear fracture,and the strength is decreases first and then increases with increasing Zr content,while the elongation is increases first and then decreases.When the Zr content is 40 at.%,the yield strength of the alloy is the minimum(736.44 MPa),and its elongation reaches a maximum(44.74%),the alloy has the best plasticity at this point.In 1mol/L HCl solution,the corrosion resistance of the alloy are increases first and then decreases with increasing Zr content.The alloy with Zr content of 40 at.% has the best corrosion resistance.