Hot Isostatic Pressing Process Research Articles

Fundamental aspects of functional grading via powder hot isostatic pressing – Development of microstructure and diffusional processes

Functional grading of a ferritic steel (SA508 grade 3) and austenitic stainless steel (316L) powder via hot isostatic pressing (HIP) consolidation is investigated as an alternative to dissimilar welding. Fundamental aspects of this method such as the development of microstructure and diffusional processes during the HIP process of such mixed powder are studied in this work. A change of the post-HIP α to γ ratio with HIP temperature was observed in mixed powder specimens, combined with the formation of a ferritic lath zone which affects the properties of the specimens (throughout this work the term ferritic laths refers to a ferritic phase of unknown structure which is likely to consist of martensite, bainite or a mixture of both). These effects were attributed to extensive diffusion of alloying elements from 316L into SA508 grade 3. Simulation and experimental quantification of diffusion in diffusion couple experiments were applied to derive an empirical model for estimating α-Fe boundary migration and the formation of the ferritic lath zone and phase fractions for various temperatures and dwell times of the HIP process.

Effect of solution heat treatment and hot isostatic pressing on the microstructure and mechanical properties of Hastelloy X manufactured by electron beam powder bed fusion

• As-built PBF-EB Hastelloy X has anisotropic microstructure and mechanical behavior. • Grain coarsening from solution heat treatment and HIP reduced the yield strength. • Crystallographic texture along 〈100〉 remained unaffected even after post-treatment. • Anisotropy in yield strength and ductility weakened following post-treatment. • Solid solution strengthening is the main contributor towards overall yield strength. Prior to the application of AM components for critical applications, it is necessary to have a better understanding of the effect of different post-fabrication treatments on the microstructure and mechanical properties of such parts. In this study, efforts were made to achieve an in-depth understanding of the effect of post-fabrication Solution Heat Treatment (SHT) and Hot Isostatic Pressing (HIP) on the microstructure and mechanical properties of Hastelloy X parts built by electron beam powder bed fusion (PBF-EB) process. The effects of SHT and HIP on porosity, microstructure, texture and mechanical properties have been investigated and compared with that of as-built PBF-EB Hastelloy X. Post-fabrication HIP treatment led to a significant reduction in the porosity content, whereas no notable difference in porosity was observed between SHT and as-built parts. There was no evidence of any recrystallization occurring following the post-fabrication treatments as elongated columnar grain structures observed within as-built part were found to be maintained even after SHT and HIP process alongside the strong 〈100〉 crystallographic texture. Emphasis was laid upon understanding the influence of SHT and HIP on mechanical properties through stress-strain curves and work-hardening behaviour.

Effect of post-processes on the microstructure and mechanical properties of laser powder bed fused IN718 superalloy

The post-processing on the additively manufactured component is of huge interest as the key to tailor the microstructure to obtain certain mechanical properties. In this present study, the effects of hot isostatic pressing, as well as heat treatment on the microstructure, phase configuration and mechanical properties of laser powder bed fused (LPBF) IN718 superalloy were systematically investigated. Three different post-processes were studied such as hot isostatic pressing (HIP), heat treatment (HT), and HIP followed by HT (HIP+HT). The HIP process effectively eliminated the Laves phase remained in the as-built microstructure and brought uniformly distributed super fine γ″ precipitates in nano-meter size. In the heat-treated microstructure, larger γ″ precipitates were promoted directly from the as-built material. In comparison the HIP+HT process caused a moderate growth of γ″. In the latter two cases, the developed γ″ significantly strengthened the material. Yield strength of IN718 was increased from 738 MPa in as-built condition to 1015 MPa and 1184 MPa after HT and HIP+HT, respectively. On the contrary the ductility in the as-built IN718 condition was reduced by more than 40% after HT and HIP+HT. This can be compared to an increase in the ductility by almost 30% when subjected the as-built specimens to only HIPping. Finally, the correlation between microstructure evolution and mechanical properties is discussed in detail.

Investigation of the effect of HIP processing on the physical and mechanical characteristics of parts obtained by the SLM method

In this paper presents the results of studying the powder material AISI 321. Selective laser melting (SLM) of the samples was carried out in modes with a change in the radiation power. The subsequent processing of the samples by the method of hot isostatic pressing (HIP) was carried out. The roughness of the surfaces and the microhardness of the samples before and after the HIP were studied.

Modelling and simulation of densification and σ-phase precipitation in PM duplex steel AISI 318LN during hot isostatic pressing

Following the development of hot isostatic pressing (HIP) with integrated rapid cooling technology, it is now possible to combine consolidation of encapsulated powder and subsequent heat treatment in a single process step in a pressure vessel. Using this technology, a near-net-shape product with target microstructure can be achieved. However, qualified final products still require traditional expensive and time-consuming trial-and-error tests. To eliminate these costly trial-and-error tests and achieve the required final properties of the products, it is urged to develop a combined numerical model to precisely predict the geometrical changes of the component during the HIP process and the evolution of significant microstructural features. This is realised in this work exemplarily by using duplex stainless steel AISI 318LN. This steel was selected due to requirements coming from applications regarding precise complex shaped near-net-shape components combined with high strength and toughness by avoiding brittle σ-phase precipitation. In this study, an existing finite element model for the densification in the HIP process was supplemented by a model for σ-phase precipitation kinetics based on microscopical characterisation. Moreover, the temperature dependent heat transfer coefficient (HTC) was implemented in the developed model to simulate the evolution and the distribution of the σ-phase during cooling. The numerically simulated final component dimensions and σ-phase volume fractions were verified by comparing with experimental data obtained from specimens and components of various shapes produced by both conventional HIP process and HIP with integrated rapid cooling. The high consistency between experimental and numerical results validates the accuracy of the developed simulation approach.

Two-step heat treatment for laser powder bed fusion of a nickel-based superalloy with simultaneously enhanced tensile strength and ductility

Nickel-based superalloys show severe cracking tendency during laser powder bed fusion (LPBF), which hinders their widespread applications in aerospace. A two-step heat treatment, including hot isostatic pressing (HIP) and solid solution heat treatment (SSHT), was proposed to obtain crack-free LPBF nickel-based superalloy components with a supersaturated solid solution of alloying elements for desirable mechanical performance. The HIP process aimed to annihilate microcracks, and the subsequent SSHT focused on modifying the microstructure and improving the solid solution extent of alloying elements. The pore-and-microcrack-containing defects with a volume fraction of 0.96% in the LPBF samples were transformed to pore-dominated defects with a volume fraction of 0.08% after the HIP process. After the SSHT, it was not observed the reappearance of the previously coalesced microcracks, but the porosity volume fraction showed a slight rebound to 0.11% due to the coarsening or regrowth of the pores. The tensile strength and elongation at break of HIP + SSHT samples printed along the horizontal plane at room temperature were 3.6% and 113.5% higher than those of as-fabricated ones. An 11.9% and 410.0% improvement in tensile strength and ductility at 900 ℃ was achieved after the two-step treatment. The development of the microstructure after the HIP and SSHT, involving sub-grains, dislocation networks, carbide precipitates, and grains, was revealed systematically. The correlation between the microstructure and tensile properties was unveiled in depth. This work is anticipated to provide an efficient route with excellent industrial applicability for LPBF superalloy components to mitigate microcracks and acquire attractive mechanical properties.

High and low-cycle-fatigue properties of 17\u20134 PH manufactured via selective laser melting in as-built, machined and hipped conditions

In the last years, additive manufacturing (AM) has turned into an emerging technology and an increasing number of classes of material powders are now available for this manufacturing process. For large-scale adoption, an accurate knowledge of the mechanical behaviour of the resulting materials is fundamental, also considering that reliable data are often lacking and dedicated standards are still missing for these AM alloys. In this regard, the aim of the present work is to characterize both the high-cycle-fatigue (HFC) and the low-cycle-fatigue (LCF) behaviour of AM 17–4 PH stainless steel (SS). To better understand the performance of the selected alloy, four series of cylindrical samples were manufactured. Three series were produced via selective laser melting (SLM), better known as laser-based powder bed fusion of metals technology using an EOS M280 machine. The first series was tested in the as-built condition, the second was machined before testing to obtain a better surface finishing, while the third series was post-processed via hot isostatic pressing (HIP). Finally, a fourth series of samples was produced from the wrought 17–4 PH material counterpart, for comparison. The understanding and assessment of the influence of surface finishing on the fatigue behaviour of AM materials are fundamental, considering that in most applications the AM parts may present reticular or lattice structures, internal cavities or complex geometries, which must be set into operation in the as-built conditions, since a surface finishing postprocess is not convenient or not feasible at all. On the other side, a HIP process is often suggested to reduce the internal porosities and, therefore, to improve the resulting mechanical properties. The high-cycle-fatigue limits were obtained with a short staircase approach according to the Dixon statistical method. The maximum number of cycles (run-out) was set equal to 50,00,000. The part of the Wöhler diagram relative to finite life was also characterized by means of additional tests at higher stress levels. On the other side, the low-cycle tests allowed to tune the Ramberg–Osgood cyclic curves and the Basquin–Coffin–Manson LCF curves. The results obtained for the four different series of specimens permitted to quantify the reduction of the mechanical performance due to the actual limits of the laser-based powder bed fusion technology (surface quality, internal porosity, different solidification) with respect to traditional manufacturing and could be used to improve design safety and reliability, granting structural integrity of actual applications under elastic and elasto-plastic fatigue loads.

Enhancement of transport J c in (Ba, K)Fe2As2 HIP processed round wires

Iron-based superconductors have become a promising candidate for high-field applications due to their high transition temperature, ultra-high upper critical field, and low anisotropy. For practical applications, it is important to improve the transport J c and lower the cost of superconductors. In this paper, with groove rolling and hot isostatic pressing (HIP) process, the transport J c of the Cu/Ag composite sheathed (Ba, K)Fe2As2 powder-in-tube round wires was increased to 4.7 × 104 A cm−2 at 10 T and 4.2 K. The utilization of HIP and groove rolling process improved the mass density of the wire. Moreover, a certain axial texture was introduced through groove rolling. It is suggested that the combination of groove rolling and HIP processes are of great help to improve the microstructure of the wires, thereby obtaining a higher transport J c.

Effect of the particle size distribution on physical properties, composition, and quality of gas atomized Astroloy powders for HIP application

Hot Isostatic Pressing (HIP) is a well-known technique that lately is gaining more interest because of its growing involvement in the Additive and Near-Net Shape manufacturing fields. When HIP is used for near-net-shape manufacturing, the raw gas atomized powders assume the uttermost importance, and special attention should be given to their quality and characteristics. Based on this statement, the powder should be sieved directly after production to select only those that best suit the HIP process. Typically, a broad Particle Size Distribution is indicated for HIP purposes and looks economically advisable because it leads to a higher yield. Despite this, if the PSD is not strictly controlled, particles with high Oxygen content or chemical inhomogeneity could enter the production chain, leading to compacted components with insufficient mechanical properties. In this paper, Nickel-based superalloy Astroloy particles were assessed in depth both at their surface and in the core, dividing them into sub-batches via mechanical sieving. This procedure evidenced which contribution was brought to the final raw material by each sub-batch. Furthermore, physical properties such as flowability and tap density were studied as a function of the PSD. Next, a complete morphological assessment was conducted to understand the possible defects of each sub-batch better. Similarly, every particle group was chemically studied to determine the Oxygen, Carbon, Nitrogen, and Hydrogen content of each sub-batch. Micro and nano indentations combined with EBSD were used to understand how the particle size may affect the mechanical properties of the powders during the Hot Isostatic pressing. Furthermore, EDS and XRD analysis were used to thoroughly understand how Ti segregation starts forming and what effects are likely to develop. Based on these investigations, it was possible to rationally identify the upper and lower boundary for particle PSD without excessively limiting the overall process yield.

Evolution of the Microstructure and Mechanical Properties of a Ti35Nb2Sn Alloy Post-Processed by Hot Isostatic Pressing for Biomedical Applications

The HIP post-processing step is required for developing next generation of advanced powder metallurgy titanium alloys for orthopedic and dental applications. The influence of the hot isostatic pressing (HIP) post-processing step on structural and phase changes, porosity healing, and mechanical strength in a powder metallurgy Ti35Nb2Sn alloy was studied. Powders were pressed at room temperature at 750 MPa, and then sintered at 1350 °C in a vacuum for 3 h. The standard HIP process at 1200 °C and 150 MPa for 3 h was performed to study its effect on a Ti35Nb2Sn powder metallurgy alloy. The influence of the HIP process and cold rate on the density, microstructure, quantity of interstitial elements, mechanical strength, and Young’s modulus was investigated. HIP post-processing for 2 h at 1200 °C and 150 MPa led to greater porosity reduction and a marked retention of the β phase at room temperature. The slow cooling rate during the HIP process affected phase stability, with a large amount of α”-phase precipitate, which decreased the titanium alloy’s yield strength.

Enhancing Transport Performance in 7-filamentary Ba0.6K0.4Fe2As2 Wires and Tapes via Hot Isostatic Pressing

Iron-based superconductors (IBS) are considered as potential materials for manufacturing high-field magnets, for which developing multi-filamentary conductors with high performance and high strength is essential. Herein, 7-filamentary Cu/Ag composite sheathed Ba0.6K0.4Fe2As2 (Ba122) round wires and tapes were successfully prepared through the ex situ powder-in-tube (PIT) method and treated by hot isostatic pressing (HIP) process. Pure Ba122 phase with roughly homogeneous element distribution was obtained in the superconducting filaments. The wires and tapes show very small low-temperature normal-state resistivity of 0.12 μΩ cm and 0.17 μΩ cm respectively owing to the high electrical conductivity of copper and silver. The HIP process greatly enhances the mass density of the superconducting filaments and promotes the formation of well-grown plate-like Ba122 grains. Vickers hardness measurements on the cross sections of these filaments reveal a rather good uniformity of the mass density. The transport critical current density (Jc) in the 7-filamentary Ba122/Ag/Cu round wires and tapes reached 1.3 × 104 A cm−2 and 4.8 × 104 A cm−2 at 4.2 K in 10 T respectively. These results indicate that hot isostatic pressing is advantageous in developing high-performance multi-filamentary iron-based superconductors.

Tailor-made functional composite components using additive manufacturing and hot isostatic pressing

ABSTRACT The combination of Additive Manufacturing (AM) and Hot Isostatic Pressing (HIP) offers great potential for industrial applications. Skilfully connecting AM and HIP creates a manufacturing process that unites the advantages of the two approaches. We demonstrate a production route for composite components by combining AM and HIP: a HIP capsule made of corrosion resistant steel is additively manufactured using Powder Bed Fusion with Laser Beam (LPBF). Before LPBF, the distortion and shrinkage of the capsule due to HIP is compensated by optimising the capsule’s geometry using Finite Element (FE) simulation of the HIP process. The capsule is filled with steel powder and manufactured by a conventional powder HIP. After HIP, the capsule remains as an outer layer on the component, so that a functional net-shape composite component is produced. Subsequent investigations show that a complex extruder screw segment can be successfully produced with a geometrical deviation smaller than 1.5%.

Reverse effect of hot isostatic pressing on high-speed selective laser melted Ti–6Al–4V alloy

Abstract Despite recent progress in achieving high mechanical properties of 3D printed metal products, the low productivity still remains a major limitation for their cost-effective feasibility in practical applications. To achieve high-speed printing with affordable mechanical properties, we increased the scanning speed of selective laser melting process with Ti–6Al–4V up to 1800 mm/s and applied a hot isostatic pressing (HIP) process to compensate for the porosity. In these high-speed printed specimens, the HIP process led to a microstructural change from αʹ-lath martensite to a Widmanstӓtten α-lamellar structure, which deteriorated their tensile properties due to the segregation of β-stabilizing atoms and caused inter-lamellar fracture. The deterioration phenomenon of high-speed printed Ti–6Al–4V specimens after the HIP process was found to be critically affected by the surface roughness of as-built state, which can be efficiently controlled with a build angle set-up.

Productivity enhancement of laser powder bed fusion using compensated shelled geometries and hot isostatic pressing

In laser powder bed fusion (L-PBF), the mechanical performance and especially fatigue properties of fabricated parts are significantly improved by hot isostatic pressing (HIP) as the density increases (pores are closed) and the microstructure improves. HIP ensures consistent and defect-free material, and consequently, this high temperature and high pressure process is often a requirement for safety-critical aerospace applications. The use of HIP to directly consolidate intentionally-unmelted interior powder in a L-PBF part was recently demonstrated. By confining the laser melting to only the outer shell (contour) of the structure, L-PBF production times can be dramatically reduced. A subsequent HIP cycle, which may be mandatory for reliability reasons, and therefore does not add additional costs, is then used to densify the entire structure. Production rates and energy efficiencies can therefore be improved in this way. This study explores the effect of relying on the HIP process to consolidate interior sections of test coupons, for which micro computed tomography (microCT), process simulation and tensile tests were conducted. MicroCT of coupons with varying shell thicknesses identify the minimum shell thickness required; and provide indications of the shrinkage ratio as a function of powder content relative to shell thickness. Preliminary results are included in which the shrinkage can be compensated for during design, by way of a “bloated cube” which collapses to a nominal cube geometry after HIP. The mechanical evaluation of the consolidated shelled parts indicates that their tensile performance is equivalent to those observed on fully dense printed parts. Up to an order of magnitude faster build rates are possible and any resulting shrinkage or distortion can be offset at design.

Effects of hot processes on microstructure evolution and tensile properties of FGH4096 Ni-based superalloy processed by Laser Powder Bed Fusion

Hot Isostatic Pressing (HIP) is one of the most important manufacturing processes to improve the performance of powder metallurgy nickel-based superalloys produced by Laser Powder Bed Fusion (LPBF), which can effectively reduce the pores and cracks in the LPBF alloys. However, there are limited studies on the effects of tuning HIP parameters on the LPBF alloys microstructure and mechanical performance. In this paper, we systematically studied the effects of hot processes on the microstructural evolution and tensile properties of an LPBF prepared typical second generation of powder metallurgy (PM) nickel-based superalloy which was designated as FGH4096. The as-deposited alloy was HIP treated at sub-solvus, solvus, and super-solvus temperature, respectively, followed by an optimized heat treatment (HT). The effects of HIP temperature on the microstructures and mechanical properties of the LPBF alloys were studied by Optical Microscope (OM), Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM) and Electron Backscattered Diffraction (EBSD). The results indicated that both HIP and HT processes led to recovery and recrystallization in the as-deposited alloy. During HIP, the increase of HIP temperature gradually eliminated the dendritic and equiaxed structures in the alloy while refined the grains along the long axis simultaneously. However, the columnar crystal morphology in the vertical section, together with straight grain boundaries, was still maintained during HIP. In all the HIPed alloys, the secondary γ′ precipitates were sparsely distributed, and due to the existence of continuous pressure, some grains with large strains remained. After HIP + HT, the dendritic and equiaxed structures basically disappeared. The grains with more curved grain boundaries tended to be equiaxed and irregularly shaped. Compared with other state alloys, the LPBF + HIP (solvus) + HT alloy has a more uniform and dense distribution of secondary γ′ precipitates, together with a chain distribution of block primary γ′ precipitates at the grain boundaries, which contributes mostly to the highest room and high-temperature tensile strengths. Moreover, the LPBF + HIP (solvus) + HT alloy has the lowest internal strain among the treated alloys, leading to the highest elongation.

Multi-particle FEM modeling on hot isostatic pressing of Ti6Al4V powders

The hot isostatic pressing (HIP) of Ti6Al4V powders was systematically simulated in two dimensions by using multi-particle finite element method (MPFEM) from particulate scale. Different initial packing structures formed by three kinds of powders (i.e. mono-sized powder, binary powder, and powder with normal size distribution) were firstly constructed. Subsequently, the effects of capsule shape, HIP procedure, temperature, pressure, as well as the powder type on the densification behavior of different Ti6Al4V compacts were investigated and discussed. The macroscopic property like relative density and various microscopic properties such as coordination number, stress/strain distributions of capsule and particles, deformation degree, pore filling behavior, densification mechanism and so on were quantitatively characterized. The results indicate that a larger aspect ratio (AR) is more likely to induce local order packing structure during particle rearrangement, and the proportion of powder particles with more regular deformation of Ti6Al4V compact increases after HIP. The total strain energy and deformation mechanisms of Ti6Al4V compacts are quite different with different HIP procedures. With the rise of temperature, the equivalent total strain of both the capsule and the particles became larger and the equivalent Von Mises stress decreased after HIP. In addition, Ti6Al4V powders with different size ratios will affect the performance of the compact in HIP process. The larger the particle size, the smaller the strain acting on the particle, the closer the roundness of the particle to 1. The Ti6Al4V compacts with different particle size distributions were found to exhibit different densification mechanisms. For packing of mono-sized powder, particle rearrangement destroyed bridging structure and large pores so as to accelerate the densification process. While for the Ti6Al4V compacts formed by binary powder or the powder with normal size distribution, the densification mechanism can be inferred to the extreme deformation of small particles promoting relative rigid motion of large particles.

Effect of randomly distributed fibers on residual stress of SiC/GH4738 composites

In this paper, the model of SiC reinforced superalloy composite with different fiber content is established by Monte Carlo simulation method. The process of hot isostatic pressing of SiC reinforced superalloy composite is simulated, and the residual stress distribution under different fiber content is obtained. The results show that not only the fiber content has a great influence on the residual stress of hot isostatic pressing of SiC reinforced superalloy composite, but also the fiber distribution has a great influence on the residual stress. It is necessary to establish a finite element model of different fiber distribution to simulate the process of hot isostatic pressing of SiC reinforced superalloy composite.

Influence of Trapped Gas on Pore Healing under Hot Isostatic Pressing in Nickel-Base Superalloys

Under the typical hot isostatic pressing (HIP) processing conditions, plastic deformation by dislocation slip is considered the primary mechanism for pore shrinkage, according to experimental observations and deformation mechanism maps. In the present work, a crystal plasticity model has been used to investigate the influence of applied pressure and holding time on porosity reduction in a nickel-base single crystal superalloy. The influence of trapped gas on pore shrinkage is modeled by coupling mechanical deformation with pore–gas interaction. In qualitative agreement with experimental investigations, we observe that increasing the applied pressure or the holding time can effectively reduce porosity. Furthermore, the effect of pore shape on the shrinkage is observed to depend on a combination of elastic anisotropy and the complex distribution of stresses around the pore. Simulation results also reveal that, for pores of the same shape, smaller pores (radius < 0.1 μm) have a higher shrinkage rate in comparison to larger pores (radius ≥ 0.1 μm), which is attributed to the increasing pore surface energies with decreasing pore sizes. It is also found that, for smaller initial gas-filled pores (radius < 0.1 μm), HIP can result in very high gas pressures (on the order of GPa). Such high pressures either act as a driving force for argon to diffuse into the surrounding metal during HIP itself, or it can result in pore re-opening during subsequent annealing or mechanical loading. These results demonstrate that the micromechanical model can quantitatively evaluate the individual influences of HIP processing conditions and pore characteristics on pore annihilation, which can help optimize the HIP process parameters in the future.

Degradation and Corrosion of Biodegradable Metal Zn-xCa

Zn-based biodegradable metals (BMs) are considered as new potential in osteosynthetic implant devices. In this study Ca, which acts as an essential element in the human body, is used to improve the rate of Zn degradation and corrosion. The alloy was synthesized using the powder metallurgy method with two different processes: cold pressing followed by sintering (CP-S) and hot isostatic pressing (HIP). Microstructure properties, as well as in vitro degradation and corrosion were studied to determine the effect of adding Ca. Variations in the sample consist of Zn-0.5Ca, Zn-1Ca, Zn-1.5Ca and Zn-2Ca. The results and analysis of test data show that the addition of Ca increases the rate of corrosion and degradation of the materials. Better bonding and microstructure properties are obtained in Zn-2Ca samples which form CaZn13 phases and small porosity. As for the HIP process, a better microstructure is obtained compared to CP-S.

Development of the Structure of Cemented Carbides during Their Processing by SLM and HIP

The study focuses on microstructural evolution in a WC-Co powder mixture during Selective Laser Melting (SLM) and hot isostatic pressing (HIP) processing. This powder mixture contained a 13 ± 0.6% weight fraction of Co binder and WC particles of mean size of 3.0 ± 1.9 μm. SLM of the mixture produced samples of various densities, depending on the volumetric energy density (VED) applied. High VED levels led to densities of up to 88%. The aspects affected by changes in VED included the pore density as well as the resulting types of phases and the size of WC phase particles. At high VED, the material began to develop cracks due to embrittlement. This had multiple causes: coarsening of α-phase (WC), evaporation of β-phase (Co binder), and precipitation of η-phase. At low VED levels, pores formed, typically of nonsymmetric shapes, with sizes larger than 500 μm. Subsequent HIP processing led to an increased density, up to 96% of solid material. Contributions to this increased density were provided by structure transformations, namely, coarsening of α-phase by up to 1300% when compared to the powder grain size, and formation of η-phase. The results provided a basis for steering further research to explore to a greater depth the SLM and HIP processing of selected WC-Co powder mixtures with as yet unused ranges of process parameters.