Selective Laser Melting of Tungsten-Rhenium Alloys

Abstract

Additively manufactured tungsten-rhenium alloys have been compared with pure tungsten in terms of their volumetric density, cracking behavior, microstructure, and hardness. The compositions W-5 wt.%Re and W-25 wt.%Re were explored. Increasing the rhenium content led to an increasing percentage of the theoretical density, with a maximum of 97.6% achieved with 25 wt.% Re. The characteristic cracking behavior of pure tungsten was greatly mitigated for the W-25%Re composition. Electron backscatter diffraction revealed the effect of rhenium in both reducing the average grain size and leading to a more equiaxed grain geometry. Postprocessing heat treatments were explored to heal remaining cracks in W-25%Re samples, producing a more recrystallized microstructure geometry and increasing the density to 98.8% of theoretical and the tensile strength to 659.8 MPa.

Laser Powder Bed Fusion of Molybdenum and Mo-0.1SiC Studied by Positron Annihilation Lifetime Spectroscopy and Electron Backscatter Diffraction Methods

“…One cylindrical specimen, 15 mm in diameter and 5 mm in height, was produced for each laser scan speed of 100, 200, 400, and 800 mm/s. All cylindrical specimens were printed on copper substrates with a 0.5 mm offset at an initial scan speed of 800 mm/s as described in Eckley et al [ 10 ] and Kemnitz et al [ 8 ]. Wire electrical discharge machining was used to remove the specimens from the substrate and produce two identical cross-sectional surfaces, each with a thickness of roughly 2 mm, at each scan speed.…”

“…The microstructures of additively manufactured (AM) refractory metals lack the consistent, well-organized microstructures expected from standardized, traditional processing. Due to the rapid heating/cooling cycle involved in AM methods such as LPBF, temperature gradients exist that cause thermally-induced stresses to accumulate and result in cracking as the material cools [ 10 ]. Along with lack-of-fusion defects due to insufficient energy input, key-hole pores occur when there is enough energy input to destabilize the melt pool and trap gas bubbles upon its collapse [ 11 ].…”

Preparation, Mechanical Properties and Strengthening Mechanism of W-Re Alloys: A Review

“…Arc smelting and electron beam smelting have been used to prepare W-Re alloys [ 21 ]. Arc melting is a method of melting materials by using an electric arc.…”

Advancements and Perspectives in Additive Manufacturing of Tungsten Alloys and Composites: Challenges and Solutions

“…In this review we consider all combinations of W with other elements as alloys and refer to combinations of W with ceramic materials (such as carbides and oxides) as composites (Table 7). The AM-fabricated alloy groups that have been studied include W-Re [139][140][141], W-Ni [94,142], W-Ni-Fe [91,92,95,97,98,101,103,119,[143][144][145], W-Ni-Fe-Co [146], W-Ni-Fe-Cu [98], W-Ni-Cu [28,147], W-Cu [28,30,[148][149][150], W-Cu-Sn [151], W-Ta [32,[152][153][154][155], W-Ta-Re [156,157], W-Nb [124], W-Fe [93,158], W-Mo [159], and W-Cr [104]. W-based matrix composites with different ceramic phases such as TiC [160,161], ZrC [134], TaC [162], La2O3 [63], CeO2 [63], a mix of La2O3 -ZrO2 -...…”

“…Enhancement of grain boundary cohesion Boosting dislocation mobility and lowering DBTT, reducing embrittlement W when alloyed with rhenium (Re) showcases a reduced DBTT and increased low-temperature ductility. This improvement is attributed to rhenium's high solubility in tungsten and its capability as a solution hardener [139][140][141] TiC, ZrC, TaC, Y2O3, La2O3, etc.…”