Novel Crystal Growth of In Situ WC in Selective Laser‐Melted W–C–Ni Ternary System

Abstract

The bulk-form in situ WC-based cermets were prepared by selective laser melting of W-C-Ni ternary powder system. The in situ formed WC crystals generally had a unique triangular microstructure which was developed via a layer-by-layer growth mechanism by the multilayered stacking of (0001) basal planes of WC. An increase in the applied laser energy density, which was realized by increasing laser power or decreasing scan speed, resulted in the coarsening of in situ WC crystals in both side length and thickness, due to the elevated heat accumulation at the tips of the triangular WC crystals.A. Bandyopadhyay-contributing editor Manuscript No. 34141.

Process development for the laser powder bed fusion of WC‐Ni Cermets using sintered‐agglomerated powder

“…The process parameters used in the fabrication of the cylinders produced specimens with a relative density range between 83.4% and 99.5%. The maximum density in this build is higher than those reported in previous LPBF WC‐Ni studies 28–30 . Several sectioned and polished specimens from different locations in the processing space (as indicated in Figure 6) are shown in Figure 7.…”

“…The maximum density in this build is higher than those reported in previous LPBF WC-Ni studies. [28][29][30] Several sectioned and polished specimens from different locations in the processing space (as indicated in Figure 6) are shown in Figure 7. Lack-offusion porosity appears to be the main mechanism behind F I G U R E 6 Relative densities of cylinders built by processing parameter combinations superimposed over the melting behavior of the powder evaluated from the single bead (SB) experiment the resulting porosity of the printed samples, similar to that of metal alloys.…”

“…The LPBF of WC‐Ni cermets, our material system of interest, was reported in several studies. Gu and Meiners 28 and Gu and Jia 29 processed in situ WC‐Ni based cemented carbides using a mechanically mixed W‐C‐Ni ternary powder system in the LPBF process; this approach resulted in samples with a maximum relative density of about 96% and the formation of unwanted complex carbides that can compromise mechanical strength. In another study, Li et al.…”

Textures formed in a CoCrMo alloy by selective laser melting

“…By repeating this process a number of times a solid 3D object of intended shape could be fabricated [4]. Previous works in recent years have demonstrated the feasibility of using this method to build 3D part from a range of metal powders, including pure iron [5], stainless steel [6][7][8], hard tool steel [9,10], titanium alloys [11][12][13][14][15], nickel-base superalloys [4,[16][17][18], cobalt-chromium alloys [19][20][21], copper compounds [22][23][24], aluminum alloys [15,[25][26][27], refractory metals [28][29][30][31], metal matrix composites (MMCs) [2,[32][33][34][35], and even dissimilar metals (functionally gradient materials) [36,37]. Glass [38,39] and metal glass [40][41][42], quasicrystals [43] are also reported as potential SLM materials in this year.…”

Taguchi-based experimental investigation into weld cladding of Ni-WC MMC overlays by CMT process

“…EDS analysis results on these precipitates (see Table 10 , points 3–6) indicate high W and C concentrations ranging from 69 to 72 wt.% and 18 to 21 wt.%, respectively; therefore, these tiny particles can be identified as primary WC precipitates formed from free W and C (due to dissolution of WC particles) in the molten pool during the solidification process, as also reported in previous literature [ 16 , 18 , 42 , 55 ]. The formation of primary WC can be realized by considering the C-rich side of the Ni–W–C ternary phase diagram [ 56 ], where WC grains develop into a three-dimensional triangular prism via a layer-by-layer growth mechanism. Random cross-sectioning of primary WC triangular prism [ 57 ] is responsible for the different morphology observed, varying from equilateral triangles, isosceles triangles, and irregular triangles to quadrilaterals [ 42 ].…”