As-built State Research Articles

Correlation between pre- and post-treatments of additively manufactured 316L parts and the resulting low cycle fatigue behavior

PurposeThe currently existing restrictions regarding the deployment of additively manufactured components because of poor surface roughness, porosity and residual stresses as well as their influence on the low-cycle fatigue (LCF) strength are addressed in this paper.Design/methodology/approachThis study aims to evaluating the effect of different pre- and post-treatments on the LCF strength of additively manufactured 316L parts. Therefore, 316L specimens manufactured by laser powder bed fusion were examined in their as-built state as well as after grinding, or coating with regard to the surface roughness, residual stresses and LCF strength. To differentiate between topographical effects and residual stress-related phenomena, stress-relieved 316L specimens served as a reference throughout the investigations. To enable an alumina coating of the 316L components, atmospheric plasma spraying was used, and the near-surface residual stresses and the surface roughness are measured and investigated.FindingsThe results have shown that the applied pre- and post-treatments such as stress-relief heat treatment, grinding and alumina coating have each led to an increase in LCF strength of the 316L specimens. In contrast, the non-heat-treated specimens predominantly exhibited coating delamination.Originality/valueTo the best of the authors’ knowledge, this is the first study of the correlation between the LCF behavior of additively manufactured uncoated 316L specimens in comparison with additively manufactured 316L specimens with an alumina coating.

Evaluation of in-situ alloyed Inconel 625 from elemental powders by laser directed energy deposition

Additive manufacturing (AM) is becoming a mainstream technique for the fabrication of performance-critical products. In-situ alloying from elemental powders shows enormous potential to realize cost-effective alloy development and reduce the complexity of powder material management for industry. In this study, laser directed energy deposition (DED) was applied to investigate the feasibility of in-situ alloying of Inconel 625 using elemental powders. Three levels of laser scanning speed were used to illustrate its effects on the microstructure and mechanical properties of in-situ alloyed samples. It was discovered that the lower laser scanning speed favors uniform in-situ alloying. At the lowest scanning speed adopted, the existence of unmelted particles is almost negligible. Moreover, at the as-built state, the in-situ alloyed Inconel 625 obtained at the lowest laser scanning speed has an averaged ultimate tensile strength of 1020 MPa, and an averaged fracture strain of 23.14%, comparable to those obtained using pre-alloyed powders under the same DED process condition. Meanwhile, its micro-hardness is 339 HV, higher than that made by pre-alloyed powders (298 HV). Microstructure characterization was also performed to reveal the underlying mechanism of in-situ alloying. This study not only demonstrates that quality Inconel 625 components can be additively manufactured through in-situ alloying from elemental powders, but also provides insights on alloy development using the flexible, high-throughput approach.

Size effect due to contour laser scanning in 316L stainless steel produced by laser powder bed fusion

In this work, effect of sample size on mechanical properties in the net-shaped 316 L alloys produced by laser powder bed fusion (LPBF) was studied. Tensile specimens with four different geometries, having the same total cross-sectional areas but with different tension beam widths of 0.75, 1.5, 3 and 6 mm, were produced by the LPBF and subjected to the tests. The experimental results indicated that there is a strong influence of the sample size of the mechanical properties in the as-built state. The yield strength increased and the ductility decreased pronouncedly with decreasing the sample size. Fine grain structures near the surface of the net-shaped samples due to the additional laser contour scanning is believed to be responsible to the strong sample size effect. The experiments also revealed that the sample size effect can be effectively reduced with the annealing heat treatments. The local strength of the fine-grained area near the surface was quantitatively characterized by an inverse finite element analysis. The local strength near the surface was found stronger in the direction parallel to the LPBF building direction than in the direction parallel to the LPBF transverse direction, leading to more significant size effect along this direction.

Influence of high initial porosity introduced by laser powder bed fusion on the fatigue strength of Inconel 718 after post-processing with hot isostatic pressing

Laser-based additive manufacturing (AM) of metallic materials can produce AM parts of high quality. The obtained density of metal parts manufactured by laser powder bed fusion (LPBF) is mostly greater than 99% and high mechanical strengths can be achieved; however, a long processing time is typically required to reach a high quality. Possibilities to shorten the LPBF processing time involve increasing either the scanning speed or the hatch distance, but both will result in greater porosity. In general, the porosity of AM parts can be reduced by subsequent post-densification of the materials by hot isostatic pressing (HIP). In this manner, not only can the LPBF process be accelerated but the fatigue strength of the parts can be increased by reliable reduction of porosity and the simultaneous homogenization of the microstructure. Nevertheless, argon porosity introduced by the LPBF process cannot be completely eliminated by HIP due to the insolubility of argon in metallic materials. In the present study, the influence of the initial porosity on the fatigue strength of IN718 specimens after HIP and different heat treatments were investigated with a view to understanding the impact of argon porosity. The fatigue strength under a rotating bending load was determined for four different test batches and one almost fully dense as-built state as a reference. For the test batches, two different initial porosities of 3.5% and 9.9% were introduced by increasing the hatch distance. These porous samples were subjected to the same HIP treatment but aged differently: half of the samples were annealed, quenched, and aged within the HIP vessel under pressure and the other half were annealed and quenched within the HIP vessel but aged in an ambient air atmosphere. HIP post-processing significantly improved the fatigue strength of IN718 samples produced by LPBF, even in the case of a high initial porosity and residual argon content. In the case of a 3.5% initial porosity, no difference was observed in fatigue behavior with respect to aging with or without pressure. In contrast, samples with an 9.9% initial porosity showed a large difference in fatigue strength according to different aging conditions.

TiB reinforced Ti-6Al-4V matrix composites with improved short-term creep performance fabricated by laser powder bed fusion

This study investigates the short-term creep performance of laser powder bed fusion (L-PBF) fabricated Ti-6Al-4V (Ti64) and TiB-reinforced Ti64 matrix composite (TMC) parts. The TMCs were fabricated by L-PBF processing of 0.2wt.%B4C/Ti64 composite powder. The optimum set of process parameters was used to manufacture creep test specimens. In addition to the as-built scenario, supertransus heat treatment was conducted to eliminate the microstructural anisotropy. Creep testing of the as-built and heat-treated samples was performed at 600 °C under a constant tensile stress of 200 MPa. Microstructural evolutions were scrutinized before and after the creep test. Results revealed a slightly longer rupture time for Ti64 than the TMC part in the as-built state. Although the boundaries of prior β grains were detected as the preferential void nucleation sites in both as-built samples, the TMC part featured a significantly higher frequency of smaller voids near the fracture location. The heat-treated Ti64 sample showed the most inferior creep performance with a premature failure due to continuous networks of grain boundary α (GB-α). However, the heat-treated TMC counterpart showed a noticeably improved creep performance with a rupture time of 5.8 h owing to the absence of GB-α, presence of hard and stiff TiB reinforcements, and the increased fraction of interfaces (α-α, α-β, and α-TiB).

Investigations of powder reusing on microstructure and mechanical properties of Inconel 718 obtained by additive manufacturing

Laser powder bed fusion, largely employed for additive manufacturing, induces after each batch a large quantity of remaining powder. This study focuses on the possibility to reuse this remaining powder after a large number of production cycles and on the influence of such reusing on the microstructure and mechanical properties. Inconel 718 parts made from fresh and 50 times reused powder were processed and then characterized in the as-built state. The effect of powder reuse on the microstructure was assessed thanks to a multiscale study and the resulting mechanical response was evaluated using both monotonous and cyclic tests. Our results clearly show that despite a better powder flowability for the reused powder, only minor differences between the two investigated materials demonstrating the possibility of high-quality parts production from reused powders.

Ballistic impact resistance of additive manufactured high-strength maraging steel: An experimental study

Maraging steel is a low carbon steel known for its ultra high-strength after heat treatment. In combination with Additive Manufacturing (AM), the properties of maraging steel indicate potential to enable complex geometries and improved performance-to-weight ratios for ballistic protection. This study investigates the ballistic performance of AM maraging steel monolithic plates and profile panels fabricated by powder bed fusion. The mechanical properties of the maraging steel, both in the as-built state and after heat treatment, were revealed through quasi-static and dynamic tests in three different directions with respect to the build direction. Metallurgical studies were also conducted to investigate the microstructure of the material both before and after testing. The ballistic perforation resistance of the maraging steel samples was disclosed in a ballistic range by firing 7.62 mm APM2 bullets towards the different target configurations. Ballistic limit curves and velocities were obtained, demonstrating that the thickest heat-treated AM maraging steel plate has a particularly good potential for ballistic protection. The hard core of the armour piercing bullet broke in all tests and occasionally shattered during tests with heat-treated targets. However, due to the severe brittleness of the material, the targets showed significant fragmentation in some cases and most significantly for the profile panels.

Fatigue crack growth in IN718/316L multi-materials layered structures fabricated by laser powder bed fusion

Multi-materials additive manufacturing (MMAM) allows the functional optimisation of components by tailoring the addition of alloys at different design locations in a single operation. In this study Laser Powder Bed Fusion (L-PBF) technique was used to manufacture layered specimens combining IN718 and 316L materials. The microstructure and mechanical properties were studied by scanning electron microscopy (SEM), tensile, micro and nanohardness testing. The fatigue tests were performed to determine the crack propagation process through multi-layer specimens in the as-built (AB) state.

In Situ Alloying of a Modified Inconel 625 via Laser Powder Bed Fusion: Microstructure and Mechanical Properties

This study investigates the in situ alloying of a Ni-based superalloy processed by means of laser powder bed fusion (LPBF). For this purpose, Inconel 625 powder is mixed with 1 wt.% of Ti6Al4V powder. The modified alloy is characterized by densification levels similar to the base alloy, with relative density superior to 99.8%. The material exhibits Ti-rich segregations along the melt pool contours. Moreover, Ti tends to be entrapped in the interdendritic areas during solidification in the as-built state. After heat treatments, the modified Inconel 625 version presents greater hardness and tensile strengths than the base alloy in the same heat-treated conditions. For the solution annealed state, this is mainly attributed to the elimination of the segregations into the interdendritic structures, thus triggering solute strengthening. Finally, for the aged state, the further increment of mechanical properties can be attributed to a more intense formation of phases than the base alloy, due to elevated precipitation strengthening ability under heat treatments. It is interesting to note how slight chemical composition modification can directly develop new alloys by the LPBF process.

Microstructure and mechanical properties of hybrid additive manufactured dissimilar 17-4 PH and 316L stainless steels

Hybrid metal additive manufacturing is a novel way of combining the advantages of different manufacturing methods. It offers the freedom of fabricating functional parts with varying requirements such as size and complexity, overcoming the need for additional joining operations. On the other hand, combining dissimilar materials enables the route for obtaining different properties such as mechanical strength, high temperature and corrosion resistance in a single part body. In this study, wire arc additive manufacturing (WAAM) and laser powder bed fusion (L-PBF) technologies were combined utilizing dissimilar metals for each process. Deposition of AISI 316L stainless steel on previously L-PBF manufactured 17-4 PH stainless steel part was successfully executed using WAAM process. Microstructural observations showed five different zones in the as-built state whereas a uniform microstructure was obtained following the heat treatment as confirmed by hardness measurements. Tensile tests were conducted on the specimens extracted from the L-PBF/WAAM interface and the results showed a ductile fracture from the WAAM region, validating the strength of the interface. The tensile test results exceeded the standard strength requirements with a minor decrease in ductility.

Effect of heat treatments on the microstructure and mechanical properties of Al-Mg-Sc-Zr alloy fabricated by selective laser melting

High-strength aluminum alloy with Sc-Zr is specially optimized for Selective Laser Melting (SLM). The alloy has a great potential in structurally optimized lightweight parts in the fields of aerospace, nuclear power and automobile due to its good formability, fine microstructure, and excellent mechanical properties. An appropriate heat treatment for this alloy is critical to improve its ultimate tensile strength. However, the effect of heat treatments on the microstructure and mechanical properties of SLMed Al-Mg-Sc-Zr alloy is not fully understood and heat treatment needs to be optimized. In this investigation, the effect of 500 °C homogenization and 330 °C ageing on the microstructure and properties of the SLMed parts were investigated. The results show that a homogenization treatment at 500 °C does not increase the solubility of the alloy elements, but accelerates the precipitation of Sc/Zr elements and recrystallization. Moreover, homogenization with holding time longer than 2 h results in a decrease of mechanical properties including both tensile properties and ductility compared with those of the as-built state. Ageing treatment at 330 °C for 1 h drives the second phase of Al3(ScxZr1-x) to fully precipitate, and long-term ageing for 8 h neither leads to recrystallize nor deteriorates the properties of the alloy. A rapid ageing heat treatment at 330 °C for 1 h was explored, with a tensile strength of 479 MPa, a yield strength of 441 MPa, an elongation after break of 14.5%, and a shrinkage of 45%. Specimens of SLMed Al-Mg-Sc-Zr alloy are strengthened by fine grains whose formation is driven by extremely high temperature gradients and solidification rates, and precipitation of the second phase Al3(ScxZr1-x) caused by ageing. The Orawan bypass mechanism plays an important role in the strengthening of the aged SLMed Al-Mg-Sc-Zr alloy.

Carbon Particle In-Situ Alloying of the Case-Hardening Steel 16MnCr5 in Laser Powder Bed Fusion

The carbon content of steel affects many of its essential properties, e.g., hardness and mechanical strength. In the powder bed fusion process of metals using a laser beam (PBF-LB/M), usually, pre-alloyed metal powder is solidified layer-by-layer using a laser beam to create parts. A reduction of the carbon content in steels is observed during this process. This study examines adding carbon particles to the metal powder and in situ alloying in the PBF-LB/M process as a countermeasure. Suitable carbon particles are selected and their effect on the particle size distribution and homogeneity of the mixtures is analysed. The workability in PBF-LB is then shown. This is followed by an evaluation of the resulting mechanical properties (hardness and mechanical strength) and microstructure in the as-built state and the state after heat treatment. Furthermore, potential use cases like multi-material or functionally graded parts are discussed.

Laser Powder Bed Fusion printability of cobalt-free steel powders for manufacturing injection molds

Laser Powder Bed Fusion (LPBF) printing is used for manufacturing conformal cooling injection molds with internal cooling channels. Currently, the steel used to manufacture such molds by LPBF is the maraging 18Ni300. However, this steel is softer at high temperatures and less resistant to corrosion than the reference steel, the AISI H11. Moreover, 18Ni300 contains cobalt, an element that can be harmful to the health of people handling powders made of this steel. In order to find a cobalt-free alternative to 18Ni300, the printability of three different types of steel is studied: maraging stainless steels (CX, L40), martensitic non-stainless steels (42CD4, H11, H13, PM2012) and martensitic stainless steels (X15TN, PM420). The printability of those eight steels is studied through their mechanical properties (Rockwell hardness, Charpy impact test), their internal defects and surface roughness (X-ray tomography), the presence of cracks (optical microscope), and also through their microstructure (X-ray diffraction) in the as-built state. The results show that the stainless steels (PM420, X15TN, L40 and CX) exhibit interesting as-built properties allowing them to be considered as a possible alternative to the maraging steel 18Ni300 to produce LPBFed injection molds. A conformal cooling injection mold was then printed as a demonstrator.

Systematic exploration of the L-PBF processing behavior and resulting properties of β-stabilized Ti-alloys prepared by in-situ alloy formation

Aim of this work is to gain a comprehensive understanding of the effects of an increasing β-phase stability of Ti-alloys on the L-PBF processing behavior. For this purpose, seven different Ti-alloys with an increasing concentration of the β-phase stabilizing elements Fe and V were prepared by L-PBF and in-situ alloy formation. The Molybdenum equivalent (Moeq) of the examined alloys, as a measure of β-phase stability, was varied systematically between −3.3 and 25. It is shown that a homogeneous distribution of elements is achievable by in-situ alloying. The experiments prove that the investigated alloys can be processed by a single L-PBF parameter set with high relative density above 99.8%. This finding is substantiated by calculated thermo-physical material properties and an analytical model. To understand the underlying metallurgical effects governing the L-PBF results, the samples were investigated extensively by EDS, EBSD, XRD, light microscopy and compression tests. The β-phase fraction varies in dependence of the Moeq between 0% and 99%. Because of rapid solidification inherent in L-PBF a Moeq of 10 is sufficient to receive more than 90% β-phase. The same amount of β-phase after furnace cooling was only observed in alloys with Moeq of 20 or more. While all alloy compositions can be processed with high relative density of over 99.8%, alloys with a Moeq between 15 and 20 show a brittle material behavior in as-built state, resulting in cracking during L-PBF. This behavior is attributed to the formation of ω-phase during L-PBF. In contrast, the highest β-stabilized alloy with a nominal Moeq of 25 exhibits a very high ductility with a fracture strain exceeding 50%.

Towards a digital twin of laser powder bed fusion with a focus on gas flow variables

Metal additive manufacturing is increasingly used as a complementary manufacturing technique in industrial settings and slowly moving from pure prototyping applications toward full production. In parallel, there is an emergence of Industry 4.0, where the applicability of concepts such as digital twins of manufacturing machines and components are being investigated. Compared to conventionally manufactured parts, typical quality metrics of metal additively manufactured components such as dimensions, roughness, porosity, and hardness are underperforming in an as-built state. As a mitigation strategy, the build chamber variables are often measured and logged by the metal additive manufacturing system to maintain a stable production environment. Thus, proper insight into the expected responses in part quality from changes in those build chamber variables is important in the pursuit of digital twins and process improvement. This sheds more light on the influence of the gas flow variables, namely gas flow speed, relative pressure, and oxygen content on the metal additive manufacturing quality metrics, specifically channel roughness, bulk porosity, average diameter, the equivalent diameter of the unobstructed cross-sectional area, and hardness of the bulk. A Design of Experiments was implemented on two laser powder bed fusion systems, namely an SLM 280 processing 316L stainless steel and an SLM 500 processing Ti6Al4V. The current work found that surface oxidation of 316L and Ti6Al4V components may be classified based on simple red, green, and blue (RGB) color constituent analysis. The influence of gas flow variables was found to be different in the two investigated SLM systems, suggesting a high dependency on the processed material. Oxygen content in the build chamber had the highest standalone effect on the selected quality metrics, while the gas flow speed had the lowest standalone effect. The second-order effects were found to be, in general, more significant than the main effects. The findings of the current work is a step towards an improved understanding of the interaction effects of gas flow conditions on typical quality metrics of metal additive manufactured components. By the creation of simple but computationally fast response surface models, in-line assessments may be carried out and the effect of process variability on component quality may be evaluated in-situ while being one step away from the full feedback control implementation in the digital twin. Following the methodology of the current work for other laser powder bed fusion systems enables the generation of 3D point cloud visualizations for decision making under uncertainty.

Residual stresses and heat treatments of Inconel 718 parts manufactured via metal laser beam powder bed fusion: an overview

Additive manufacturing (AM) is a unique manufacturing process that disrupted completely the way which components are made, since this process is capable of producing complex parts layer after layer. As a matter of fact, one of its distinct technologies is metal laser beam powder bed fusion (mLB-PBF), also known as selective laser melting (SLM) or direct metal laser sintering (DMLS), which creates metallic parts with the aid of a high-energy laser beam. One of the most employed superalloys in this technology is the Inconel 718 (IN718), a precipitation-hardened alloy that is used in the marine, nuclear power plants, gas turbines, and aerospace field due to its capacity of retaining good mechanical properties at high temperatures. The research novelty of this review manuscript is the compilation of all kinds of information from the last 15 years of investigation about IN718 parts produced via mLB-PBF, namely, information related to distinct heat treatments and the influence they have in increasing mechanical properties of the manufactured components, as well as reducing residual stresses (RS) and part porosity. Throughout the review, it can be seen that the expected microstructure in the as-built state is characterized by fine columnar grains and a saturated γ matrix with the presence of the Laves phase and carbides. However, distinct heat treatments can be employed which lead to the dissolution of the undesired phases (Laves and carbides), the precipitation of the strengthening phases (γ’ and γ”), and the porosity decrease. Furthermore, it was also shown that heat treatments as well as optimized process parameters can be held accountable for lowering the RS of the IN718 manufactured parts. Nevertheless, there are still some problems to overcome, namely, the mechanical properties variability when subjecting IN718 powder to different process parameters. Moreover, the RS evolution under different heat treatments needs to be further investigated.

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.

Improving the surface quality and mechanical properties of selective laser sintered PA2200 components by the vibratory surface finishing process

This paper attempts to improve the physical and mechanical properties of selective laser sintered polyamide PA2200 components through a vibratory surface finishing process by inducing severe plastic deformation at the outer surface layers. The industrial target of additive manufacturing components is to obtain structures having surface roughness, hardness, and other mechanical properties equivalent to or better than those produced conventionally. Compared to the as-built SLS PA2200 samples, vibratory surface finishing treated specimens exhibited a smooth surface microstructure and more favorable roughness, hardness, and tensile strength. Also, the duration of the vibratory surface finishing process showed a further improvement in the surface roughness and hardness of the SLS samples. Compared to the as-built state, the roughness and hardness of the surface-treated samples improved by almost 90% and 15%, respectively. Consequently, microstructural analysis indicates that lower surface roughness and enhanced surface hardness is a crucial factor in influencing the overall tensile strength of SLS-PA2200 components. We consider that the combination of VSF and SLS processes can successfully handle a wide range of potential applications. This study also highlights the efficiency and applicability of the vibratory surface finishing process to other additive manufacturing processes and materials.Graphic abstract

Effect of input powder attributes on optimized processing and as-built tensile properties in laser powder bed fusion of AlSi10Mg alloy

A systematic material characterization approach is presented to demonstrate the critical impact of input powder attributes on the optimized parameters and the as-built properties in the Laser Powder Bed Fusion (LPBF) of AlSi10Mg alloy. Two batches of powders (conventional and specialty) with widely different attributes, including particles’ morphology, size distribution, internal oxidation, surface chemistry and roughness, were separately investigated for the optimized LPBF parameters. It is showed that the specialty powder with a spherical morphology and a larger mean particle size exhibits a higher flowability, as well as a higher apparent density. The latter, together with a smoother surface topography in the specialty powder particles (thus a lower laser absorptivity), necessitates a higher volumetric energy density (VED) requirement for a complete fusion during the LPBF. The as-built microstructures which resulted from both powders show a similar evolution of total porosity content, melt-pool boundaries and solidification structure, both qualitatively and quantitatively, which is consistent with their comparable YS values. The specialty powder, however, yields a higher UTS and %El in the as-built state, which is believed to be due to a scarce presence of O-rich particles (which otherwise preside primarily within the intercellular regions, as is the case for the conventional powder). The emergence of such O-rich particles in the as-built microstructure could be traced back to the powder source (i.e., in the form of internal O-rich phases and a thick oxide surface layer in the conventional powder). In other words, an O-lean powder translates into an O-lean printed part. One-time recycling of the specialty powder is shown to have a negligible effect on its morphological characteristics, and thus on the optimized set of parameters, consistently yielding as-built YS values similar to those of the original powder. The as-built UTS and %El values resulting from the recycled powder, however, are notably lower than those from the original powder, which are suggested to be due to the presence of contaminants and/or oxide inclusions resulting from the LPBF processing itself and/or during the recycling procedure (e.g., sieving). We believe the correlations established here between the input powder attributes and the LPBF performance of AlSi10Mg alloy can be applicable to many metallic systems.

Tailoring Microstructure and Mechanical Properties of Additively-Manufactured Ti6Al4V Using Post Processing.

Additively-manufactured Ti-6Al-4V (Ti64) exhibits high strength but in some cases inferior elongation to those of conventionally manufactured materials. Post-processing of additively manufactured Ti64 components is investigated to modify the mechanical properties for specific applications while still utilizing the benefits of the additive manufacturing process. The mechanical properties and fatigue resistance of Ti64 samples made by electron beam melting were tested in the as-built state. Several heat treatments (up to 1000 °C) were performed to study their effect on the microstructure and mechanical properties. Phase content during heating was tested with high reliability by neutron diffraction at Los Alamos National Laboratory. Two different hot isostatic pressings (HIP) cycles were tested, one at low temperature (780 °C), the other is at the standard temperature (920 °C). The results show that lowering the HIP holding temperature retains the fine microstructure (~1% β phase) and the 0.2% proof stress of the as-built samples (1038 MPa), but gives rise to higher elongation (~14%) and better fatigue life. The material subjected to a higher HIP temperature had a coarser microstructure, more residual β phase (~2% difference), displayed slightly lower Vickers hardness (~15 HV10N), 0.2% proof stress (~60 MPa) and ultimate stresses (~40 MPa) than the material HIP’ed at 780 °C, but had superior elongation (~6%) and fatigue resistance. Heat treatment at 1000 °C entirely altered the microstructure (~7% β phase), yield elongation of 13.7% but decrease the 0.2% proof-stress to 927 MPa. The results of the HIP at 780 °C imply it would be beneficial to lower the standard ASTM HIP temperature for Ti6Al4V additively manufactured by electron beam melting.