Influence Of Post Heat Treatment Research Articles

Influence of post-heat treatments on the microstructure and mechanical properties of Inconel 738 produced by laser directed energy deposition

Influence of post-heat treatments on the microstructure and mechanical properties of Inconel 738 produced by laser directed energy deposition

Influence of post heat treatment on tribological and microstructural properties of plasma wire arc additive manufactured maraging steels

Abstract Metallic alloys are increasingly being produced using wired arc additive manufacturing (WAAM). In this study, 18Ni300 defect-free maraging steels were produced using the WAAM technique. A traditional solution treatment, direct aging, and cryogenic heat treatment processes were applied to the WAAM produced maraging steels. The influence of conventional and novel cryogenic heat treatments on microstructural, mechanical, and tribological properties were examined. The microstructure of the as-built materials obtained by WAAM thermal cycling has mainly been homogenized through the solution, direct-aging, and cryogenic heat treatments. As a result, homogeneously distributed precipitate phases were obtained and the hardness increased by 30 % with a combination different post heat treatments. The cryogenic heat treatment improved the martensitic transformation and facilitated the formation of various Fe–Ni–Mo–Ti-containing intermetallic precipitates. Similarly, because of the different heat treatments, the wear resistance improved by a factor of 2–5.5 relative to the as-built material. Adding the cryogenic heat treatment to the traditional heat treatment procedure improves wear resistance by a factor of 1.2–2.9.

Influence of Post-Heat Treatment on Corrosion Behaviour of Additively Manufactured CuSn10 by Laser Powder Bed Fusion.

This study investigates the influence of heat treatments on the corrosion behaviour of CuSn10 tin bronze, additively manufactured using Laser Powder Bed Fusion (LPBF). LPBF enables the creation of finely structured, anisotropic microstructures, whose corrosion behaviour is not yet well understood. After production, specimens were heat-treated at 320 °C, 650 °C, and in a two-stage treatment at 800 °C and 400 °C, followed by hardness and microstructure analysis. Corrosion tests were conducted using linear polarisation, salt spray, and immersion tests. The results show that heat treatments at 320 °C and 650 °C have no significant effect on the corrosion rate, while the two-stage treatment shows a slight improvement in corrosion resistance. Differences in microstructure and hardness were observed, with higher treatment temperatures leading to grain growth and tin precipitates. The formation of a passive protective layer was detected after 30 h of OCP measurement. Results from other studies on corrosion behaviour were partially reproducible. Differences could be attributed to varying chemical compositions and manufacturing parameters. These findings contribute to the understanding of the effects of heat treatments on the corrosion resistance of additively manufactured tin bronze and provide important insights for future applications in corrosive environments.

Influence of Post-Heat Treatment on the Characteristics of FeCrBMnSi Coating on Stainless Steel 304 Substrate Prepared by Twin Wire Arc Spray (TWAS) Method at Various Stand-off Distance

Influence of Post-Heat Treatment on the Characteristics of FeCrBMnSi Coating on Stainless Steel 304 Substrate Prepared by Twin Wire Arc Spray (TWAS) Method at Various Stand-off Distance

Influence of post-heat treatment with super β transus temperature on the fatigue behaviour of LPBF processed Ti6Al4V

Influence of post-heat treatment with super β transus temperature on the fatigue behaviour of LPBF processed Ti6Al4V

Effect of Heat Treatment on Fatigue Performance of 316L Stainless Steel Fabricated by Laser Powder Bed Fusion

Abstract The 316L stainless steel part built by laser powder bed fusion has attracted much attention in recent years. However, current studies have not systematically revealed the influence of post-heat treatment on fatigue performance. In this study, we utilized two common heat treatment processes (450 °C anneal treatment and 1050 °C solution treatment) for 316L stainless steel and then discussed their influence on fatigue life and crack growth rate. It can be found that both the heat treatment processes led to a decrease in fatigue life. The 1050 °C solution treatment can decrease crack growth rate. This can be attributed to the increase in grain size and decline of carbide at the grain boundary. The former can lead to a longer propagation path. The latter may cause more and deeper secondary cracks along the propagation path, which exhaust more energy.

Influence of post-heat treatment on microstructure, texture, and mechanical properties of 18Ni-300 maraging steel fabricated by using LPBF technique

Influence of post-heat treatment on microstructure, texture, and mechanical properties of 18Ni-300 maraging steel fabricated by using LPBF technique

Influence of post-heat treatment with super β transus temperature on the tensile behaviour of LPBF processed Ti6Al4V

This paper investigates the tensile behaviour of Laser powder bed fusion (LPBF) processed Ti6Al4 V samples under three build orientations. The effect of microstructural changes from the post-heat treatments (PHTs – 850 °C, 950 °C 1050 °C) was assessed. The microstructural characterization was performed using optical microscopy, X-ray diffraction, and SEM techniques. The tensile tests were performed using a uniaxial universal testing machine (UTM). The fractal dimension analysis was performed on the fractured surfaces using ImageJ software integrated with an open-source MultiFrac plug-in. The PHT at a higher temperature (i.e., 1050 °C) induces a higher amount of β phase than the other PHTs. The PHT performed at 1050 °C exhibited α-Widmanstatten microstructure consisting of elongated β and a small amount of α. The PHT induces an isotropic behaviour in the LPBF-processed samples. However, the ductility of specimens subjected to PHT at 1050 °C showed ∼ 67%, 40%, and 177% improvement under horizontal (0°), inclined (45°), and vertical (90°) orientations than as-printed samples. Further fractal dimension analysis corroborates well with the ductility values of PHT samples. Therefore, the combination of fractography analysis and fractal dimension approach can be a promising methodology towards fractured surface characterization of additively manufactured metal parts.

Influence of post heat treatment on metallurgical, mechanical, and corrosion analysis of wire arc additive manufactured inconel 625

In the present research, the metallurgical and mechanical analysis along with the corrosion behaviour of Inconel 625 alloy formed by wire arc additive manufacturing-cold metal transfer (WAAM-CMT) based process were assessed with and without post heat treatments. Mechanical analysis was carried out with the help of impact and tensile strength analysis. Metallurgical analysis was conducted via. Electron Backscatter Diffraction (EBSD), SEM-EDS, and XRD. While, corrosion analysis was conducted with the help of cyclic polarization test. Cyclic polarization test unveils variations in corrosion resistance among as prepared and heat-treated samples, with water quenched showing potential for enhanced corrosion protection. Moreover, the fractured surface analysis after tensile and impact strength tests was also conducted with the help of SEM images. Overall, the designated material after heat treatment at 1100 °C for 2 h along with water quenched presents the best mechanical, metallurgical and corrosion performance for Inconel 625 developed by WAAM-CMT process.

Influence of post heat treatment on the high-temperature performances of multi-layered thermal/environmental barrier coatings on SiC-based composites

Multi-layered LaMgAl11O19/Yb2Si2O7/Yb2Si2O7–Si/Si (LMA/YbDS/YbDS–Si/Si) thermal/environmental barrier coatings (T/EBCs) on SiC fibre-reinforced SiC ceramic matrix composites (SiCf/SiC–CMCs) were subjected to post heat treatment at 1200 or 1350 °C for 5 h. The thermal cycling and water-vapour/oxygen corrosion of the multi-layered T/EBCs after annealing at different temperatures were studied. The results showed the thermal cycling lifetime of the 1350 °C-annealed T/EBCs was shorter than those of the 1200 °C-annealed and as-sprayed T/EBCs, while the 1350 °C-annealed T/EBCs exhibited relatively outstanding resistance to steam corrosion. The degraded thermal cycling lifetime may be associated with horizontal cracks generated at the interfaces of the LMA and YbDS layers after annealing at 1350 °C, which weakened the bonds between the coating layers. The outstanding resistance to steam corrosion of the 1350 °C-annealed T/EBCs could be attributed to the formation of a Yb3Al5O12 reaction layer with low-oxygen permeability on the upward sides of the YbDS layers in the 1350 °C-annealed T/EBCs. This could reduce the oxidation of Si inclusions within the YbDS layers, leading to less silica volatilisation.

Influence of post-heat treatment over structural network and mechanical properties of carbon (C)-incorporated CVD TiCN thin-film coating

Influence of post-heat treatment over structural network and mechanical properties of carbon (C)-incorporated CVD TiCN thin-film coating

Influence of post heat treatment on microstructure and fracture strength of cemented carbides manufactured using laser-based additive manufacturing

Laser-based additive manufacturing of cemented carbides (WC-Co) remains challenging due to crack forming and residual porosity. Reduction of temperature gradients by high preheating temperatures and successive thermal treatments are starting points for improving the quality of additively manufactured components. Thermal post-treatment is beneficial for the final densification and homogenization of the microstructure. In this study, hot isostatic pressing (HIP) and sinter-HIP are used for thermal post-treatment of additively manufactured parts of WC-12Co. Both methods use elevated temperatures and pressures for densification. Densification during the sinter-HIP process is achieved by liquid phase sintering, while in the HIP process, compaction is expected by plastic deformation of the material. The effect of these both methods for post-treatment on microstructure and fracture strength is investigated in this study. Subsequently, tungsten carbide grain size, as well as the composition of the binder phase, are related to these results.

Effect of post-heat treatment conditions on shape memory property in 4D printed Fe–17Mn–5Si–10Cr–4Ni shape memory alloy

The influence of post-heat treatment on the microstructure and properties of 4D printed Fe–17Mn–5Si–10Cr–4Ni (wt. %) shape memory alloy (SMA) produced via a laser powder bed fusion process is investigated in this study. It is shown that heat-treatment temperatures lower than 800 °C are not sufficient to completely undergo phase transformation from bcc-δ to fcc-γ, whereas temperatures higher than 800 °C lead to grain growth and thickening of hcp-ε phases. The latter has a severely negative effect on shape memory. Furthermore, heat treatment at 800 °C for more than 3 h leads to σ-phase formation, which also negatively affects the shape memory effect (SME) by changing the chemical composition of the fcc-γ matrix. The SME along the building direction (BD), is higher than that along the laser scanning direction (SD) and in 45° to the SD (45SD). The higher SME along the BD is attributed to the {110} texture in the plane normal to the BD, whereas almost random but weak {111} and {100} textures are observed in SD and 45SD. Furthermore, transmission electron microscopy revealed that a high stacking fault density and very thin hcp-ε phase are formed in the heat-treated sample, which explains the higher SME regardless of direction, compared with conventionally fabricated Fe-based SMAs with a similar composition.

Influence of post-heat treatment on the microstructure and mechanical properties of Al-Cu-Mg-Zr alloy manufactured by selective laser melting

The properties of modified conventional wrought aluminum alloys cannot be significantly enhanced by normal post-heat treatment in that the fine-grained strengthening, arising from high cooling rate in SLM, is underutilized. In this work, compared with the normal T6 heat treatment, a novel simple direct aging regime was proposed to maintain the grain-boundary strengthening and to utilize the precipitation strengthening of secondary Al3Zr. It was found that a heterogeneous grain structure, which consisted of ultrafine equiaxed (∼0.82 μm) and columnar (∼1.80 μm) grains at the bottom and top of molten pool, respectively, was formed in the SLM processed sample. After direct aging (DA), the ultrafine grains were maintained and a mass of spherical coherent L12-Al3Zr particles with a mean radius of approximately 1.15 nm was precipitated. In contrast, after solution treatment and aging (STA), a significant grain coarsening occurred in the equiaxed grain region. Meanwhile, the coarsening L12-Al3Zr particles, nano-sized S′ phases and GPB zones were detected in the STA sample. This subsequently induced that the yield strength of the DA sample (∼435 MPa) was higher than that of the STA sample (∼402 MPa) owing to the grain boundary strengthening and precipitation strengthening. Both the STA and DA samples exhibited a higher strength than that of the other SLMed Al-Cu-Mg series alloys; this was comparable to that of the wrought AA2024-T6 alloy (∼393 MPa). Both the STA and DA samples exhibited a higher strength than that of the other SLMed Al-Cu-Mg series alloys; this was comparable to that of the wrought AA2024-T6 alloy (∼393 MPa).

Influence of post-heat treatments on microstructural and mechanical properties of LPBF-processed Ti6Al4V alloy

Influence of post-heat treatments on microstructural and mechanical properties of LPBF-processed Ti6Al4V alloy

Influences of Post-Heat Treatment on the Microstructure Evolution and Creep Properties of Ni-Based Superalloy IN718 Fabricated by Electron Beam Melting

In this study, the Ni-based superalloy IN718, fabricated using an electron beam melting process, was investigated in as-built and various heat-treated conditions. The relationships between the microstructure characteristics and creep properties were elucidated. Under testing conditions of 650 °C and 650 MPa, the direct-aged specimen exhibited the lowest steady-state creep rate, at 0.15 × 10−8 s−1. The superior creep resistance can be attributed to the higher volume fraction of γ’/γ”-strengthening precipitates within the grain and fine δ precipitates along the grain boundaries. Being coherent to the γ matrix, the nano-sized γ’/γ” precipitates effectively hindered the dislocation motion in the grain interior. In addition, controlled grain boundary δ precipitates inhibited grain boundary sliding and decelerated the steady-state creep strain rate during creep deformation.

Influence of post-heat treatment on microstructure, mechanical, and wear properties of maraging steel fabricated using direct metal laser sintering technique

The post-heat treatment of direct metal laser sintered parts is expected to have superior mechanical properties. Therefore, the purpose of the present study is to investigate the post-heat treatment effect on the microstructure, mechanical and wear properties of direct metal laser sintering processed maraging steel. Hence, a systematic methodology for microstructural characterization, mechanical properties, and tribological performance evaluation was performed. The microstructural examinations were performed using optical and scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction technique. The micro-hardness and tensile properties were determined. The unidirectional sliding wear test was performed using a pin on disc wear testing machine for three different sliding velocities (0.8, 1.2, and 1.6 m/s) and three different normal loads (5, 10, and 15 N). The present study’s findings establish that the post-heat treatment techniques significantly altered the microstructural morphology and features. The results showed that the heat-treated sample had finer and non-continuous microstructure and more complex intermetallic precipitate phases, leading to higher hardness (∼64%) and higher tensile strength properties (70–80%) compared to the as-printed sample. The unidirectional sliding wear test results showed that the sliding velocity significantly affected frictional and wear characteristics of direct metal laser sintering processed maraging steel. The wear resistance of the heat-treated sample was three times higher than the as-printed sample, particularly at higher sliding velocities. In addition, the lower coefficient of friction values (∼24%) was observed for heat-treated sample compared to as-printed sample at higher sliding velocities. The post-heat treatment aids as an effective method to enhance mechanical properties of direct metal laser sintered parts and qualify them for tribological applications. The results endorse the suitability of the heat-treated direct metal laser sintered maraging steel in practical tool and die applications involving extreme tribological operating conditions such as higher sliding velocities and contact stresses.

Influence of post-heat treatments on fatigue response of low-alloyed carbon-manganese steel material manufactured by Direct Energy Deposition-Arc technique

The main idea of this paper is improving fatigue response of a low-alloyed carbon-manganese steel material manufactured by Direct Energy Deposition-Arc technique using post-heat treatments. Four series of fatigue specimens are machined from a 3D printed wall. The machined samples are austenitized following a direct quenching and tempering processes at two different temperatures. All samples are subjected to rotating bending fatigue loading conditions. Next, microhardness, microstructures and fracture surfaces of the fatigue samples are analysed. Despite of very low carbon content, a full martensitic transformation was observed after the post-heat treatments which resulted in considerably higher fatigue lifetimes compared to non-treated ones. The quenched samples gave the best improvement when compared to as-printed and tempered samples.

Influence of post-heat treatment on photocatalytic activity in metal-embedded TiO2 nanofibers

Influence of post-heat treatment on photocatalytic activity in metal-embedded TiO2 nanofibers

The influence of post heat treatments on the evolution of microstructure and mechanical properties of EP741NP nickel alloy produced by laser powder bed fusion

EP741NP superalloy was fabricated by laser powder bed fusion (LPBF) and subsequently subjected to different heat treatments including hot isostatic pressing (HIP), solution + aging, HIP + solution + aging. The structural features of the alloy in the as-built condition as well as after heat treatment were studied and compared to its mechanical characteristics such as hardness, tensile strength, impact strength, and compression strength at elevated temperatures. It was found that LPBF samples have a fine-grained columnar-cellular microstructure formed from colonies of primary dendrites and poor mechanical properties caused by structural defects (pores and isolated microcracks). The Laves phases of different compositions (Cr2Nb, Co2Nb and Cr2Hf) were detected in the interdendritic space. HIP contributes to elimination of microcracks, precipitation of the γ′ phase (0.5–7 μm in size), dissolution of the Laves phases, and formation of MeC carbide phases. A combination of these events increases strength and ductility of the alloy. Solution followed by aging without HIP results in formation of the fine-grained γ′ phase with size ranging from 150 nm to 2 μm, elimination of the Laves phases, and precipitation of MeC carbides (Cr23C6), which enhances strength. Ductility, however, remains low as the alloy structure still contains microcracks. The LPBF samples subjected to combined post-treatment (HIP + solution + aging) exhibit the maximum mechanical properties due to the elimination of structural defects during HIP and formation of the fine-grained γ/γ’ microstructure during solution and aging.