Research on Microstructure and Properties of W-25％Re Alloy Prepared by Selective Laser Melting
The W-25Re alloy was prepared by selective laser melting(SLM)using spherical W-25Re(wt％)alloy powder as the raw material.The effects of process parameters on the microstructure and properties of W-25Re alloy were investigated.The relative density,microstructure,phase composition,and Vickers microhardness of W-25Re alloy were characterized by analytical balance,field emission scanning electron microscope,X-ray diffractometer and microhardness tester.The results show that there are no obvious spheroidization,warping,deformation,delamination or non-forming phenomena during the preparation of W-25Re alloy by SLM.No obvious defects such as holes and cracks appear on the surface and side of the samples,and the formability of W-25Re alloy is good.With the increase in volumetric energy density(Ev),the grain morphology in the vertical plane of W-25Re alloy samples gradually changes from the mixture of equiaxed and columnar grains to coarse columnar grains.W-25Re alloy samples only contain the cubic W13Re7 phase,and the leftward shift of the diffraction peak 2θ angle is mainly caused by residual stress during the forming process.The influence of laser power and scanning speed on the relative density of W-25Re alloy is significant.When Ev is 1050 J/mm3,that is,the laser power is 210 W and the scanning speed is 200 mm/s,the W-25Re alloy sample with a relative density up to 98.493％can be obtained,of which the microhardness(HV0.2)in the horizontal and the vertical planes is as high as 5153.8 and 5101.9 MPa,respectively,which are close to the hardness value of the rolled W-25Re alloy.
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