Influence Of Heat Treatment Research Articles

Structural and morphological modification of the PEO coating on the Ti-25Ta-10Zr-15Nb alloy through heat treatment

This study aims to produce a Plasma Electrolytic Oxidation (PEO) layer on the Ti-25Ta-10Zr-15Nb alloy (TTZN) and analyze the influence of heat treatment at different temperatures without a controlled atmosphere to promote thermal oxidation, and in a vacuum (10−7 Torr), to prevent oxidation. The results showed that the PEO coating was initially amorphous, and heat treatments promoted the formation of crystalline compounds. Raising the heat treatment temperature led to higher surface roughness in all conditions. The heat treatment under vacuum reduced thickness (9 → 4 μm), while the heat treatment in air promoted a thickness increasing (10 → 174 μm) and decreased the wettability (82 → 25°) of the oxide layer. Due to oxygen diffusion, there was an increase in the hardness of the TTZN alloy at the oxide/metal interface after heat treatment in the air (268 → 504 HV, 268 → 845 HV, and 268 → 1011 HV, at 800, 1000, and 1200 °C).

Influence of Post-Weld Heat Treatment on Mechanical Properties and Microstructure of Plasma Arc-Welded 316 Stainless Steel.

This study investigates the effects of post-weld heat treatment (PWHT) on the microstructures and mechanical properties of plasma arc-welded 316 stainless steel. The experimental parameters included the solid solution temperatures of 650 °C and 1050 °C, solid solution durations of 1 h and 4 h, and quenching media of water and air. The mechanical properties were evaluated using Vickers hardness testing, tensile testing, scanning electron microscopy (SEM), and optical microscopy (OM). The highest ultimate tensile strength (UTS) of 693.93 MPa and Vickers hardness of 196.4 in the welded zone were achieved by heat-treating at 650 °C for one hour, quenching in water, and aging at 500 °C for 24 h. Heat-treating at 650 °C for one hour, followed by quenching in water and aging at 500 °C for 24 h results in larger dendritic δ grains and contains more σ phase compared to the other conditions, resulting in increased strength and hardness. Additionally, it shows wider and shallower dimple structures, which account for its reduced impact toughness.

Influence of heat treatment and forming cycle on the precise forming of AZ31 magnesium alloy sheet

Precision forming of 3 mm thick rolled AZ31 magnesium alloy sheet at 90° results in severe cracking and a considerable rebound angle. The effects of different sheet heat treatments and changes in the forming cycle on the value of the forming angle were investigated using 90° precision forming tests. The reasons of sheet cracking were examined using tensile tests and numerical simulations. Microscopic analysis and characterization techniques such as metallographic experiments, SEM observations, and EBSD tests are used to clarify the mechanism of improvement and control of the forming angle value. The results indicate that annealing treatment exhibits high sensitivity to controlling sheet cracking, but low sensitivity to controlling rebound. Among them, after heat treatment at 250 °C+1 h, the sheet no longer cracks during forming. In incomplete annealing, the more small grains produced by recrystallization and the greater the number of dimples in the fracture, the closer the forming angle is to 90°. Full annealing can result in a small reduction in the forming angle value compared to incomplete annealing treatments. After extending the forming cycle for 1 h, the increase in the ratio of dual tensile twin boundaries and low angle grain boundaries resulted in a significant decrease in the value of the forming angle and no cracking of the sheet. The increase of recrystallized tissue on the tensile side and the increase of the KAM value led to the decrease of the forming angle value to the minimum value at 300 °C+1 h heat treatment condition.

Influence of heat treatment on the microstructure evolution and corrosion performance of biodegradable Zn-Mg alloys

Zinc and zinc-based alloys have garnered increasing attention as biodegradable materials due to their excellent mechanical properties, lower degradation rates compared to magnesium, and favorable biocompatibility. This study investigates the impact of homogenization treatment on the microstructure and corrosion behavior of Zn-Mg alloys using scanning electron microscopy, X-ray diffraction, hardness testing, and accelerated corrosion immersion tests. The results reveal that homogenization treatment induces the fusion of eutectic cells within the alloys, causing significant morphological alternations in the eutectic structure and varying proportions of the Mg2Zn11 phase, These changes notably affect material properties. The raised content of Mg2Zn11 phase in the eutectic structure correlates with higher hardness but reduced corrosion resistance, whereas the reduced Mg2Zn11 phase content leads to enhanced corrosion resistance. Furthermore, in-situ corrosion observations demonstrate that corrosion initiates at the eutectic phase, with corrosion pits forming due to the ion release as corrosion progresses, leading to gradual enlargement of the corrosion pits. In summary, this study provides comprehensive insights into the microstructural changes in Zn-Mg alloys and their impact on corrosion resistance, offering valuable references for their engineering applications.

Influence of Heat Treatments on Microstructure Evolution and Indentation Response of Equiatomic AlCrFeMoNbNi High-Entropy Alloy

Influence of Heat Treatments on Microstructure Evolution and Indentation Response of Equiatomic AlCrFeMoNbNi High-Entropy Alloy

The Influence of Multi-Pass Hot Rolling Parameters and Subsequent Heat Treatment on Microstructure and Mechanical Properties of Medium-Carbon Steel

The Influence of Multi-Pass Hot Rolling Parameters and Subsequent Heat Treatment on Microstructure and Mechanical Properties of Medium-Carbon Steel

Influence of welding parameters and post weld heat treatment on mechanical, microstructures and corrosion behaviour of friction stir welded aluminium alloys

A study on how corrosion and mechanical characteristics of friction stir welded joints are affected by processing parameters employed during the welding and the post-weld heat treatment administered on the welded materials has been reported in this paper. This study specifically investigated the effects of variable parameters such as the tool rotational and welding speeds and the post-weld heat treatment on the mechanical and corrosion behaviour of the friction stir welded dissimilar 6101-T6 and 7075-T651 Aluminium Alloys. The welded samples were characterized by the evolving microstructure and mechanical characteristics. The results show that the tensile strength of the joints decreases from 154 MPa to 144 MPa when the rotational speed increases from 950 rpm to 1550 rpm. However, the tensile strength increases from 138 MPa to 154 MPa with an increase in the welding speed from 20 mm/min to 110 mm/min. This is due to high heat input at higher rotational speed which weakens the bonding strength at the joints. The corrosion behaviour was observed to differ at different parameters. The corrosion inhibition efficiency was highest at a rotational speed of 950 rpm, welding speed of 65 mm/min, and lowest at 950 rpm and 20 mm/min. It was observed that the Post-Weld Heat Treatment (PWHT) process enhanced the mechanical properties as a result of an improvement in the grain refinement but lowered the corrosion resistance. This study is significant as it informs the basis for the optimization of processing parameters and post weld heat treatment for dissimilar aluminium alloys for the grades considered in this study.

Influence of Heat Treatment on the Mechanical Properties of Fine-Grained Granite under Dynamic Impact Loading

In order to study the influence of heat treatment on the dynamic properties of fine-grained granite, an improved split Hopkinson pressure bar (SHPB) system was used to conduct impact compression tests on the granite specimens treated at 20~1000 °C under three loading rates. The experimental results show that the shape of the impact stress–strain curve is affected by the loading rate and heat treatment temperature. Under the same loading rate, the average strain rate, peak strain, and maximum strain of granite specimen exhibit a trend of “slow increasing (20~200 °C)—slow decreasing (200~400 °C)—slow increasing (400~500 °C)”. The peak stress and elastic modulus show the opposite trend. The average strain rate, peak strain, and maximum strain of the granite specimen treated at 600 °C increase significantly. The peak stress and elastic modulus decrease significantly. Within the heat treatment temperature range of 600~800 °C, the dynamic properties of granite deteriorate slowly. The average strain rate, peak strain, and maximum strain of the granite specimens treated at 900 °C and 1000 °C increase sharply, while the peak stress decreases sharply. Within the heat treatment temperature range of 600–1000 °C, the elastic modulus of the granite specimen shows an approximately linear decreasing trend. There are no changes in the mineral composition of granite within the heat treatment temperature range of 20–1000 °C. After heat treatment at 600 °C, the width of internal cracks in granite increases significantly. The width of internal cracks in the heat-treated granites at 900 °C and 1000 °C increases sharply. The change in the dynamic properties of granite is determined by the internal microstructure of the heat-treated granite at different temperatures.

Energy-Dispersive X-Ray Microanalysis – as a Method for Study the Aluminium-Polysilicon Interface after Exposure with Long-Term and Rapid Thermal Annealing

Energy dispersive X-ray microanalysis is one of the main methods for determining the elemental composition of matter. Possessing high locality and a relatively shallow penetration depth of the electron beam (< 1 μm), this method has found wide application in the field of microelectronics, as the main method for analyzing the elemental composition of matter. The method allows to study the surface of a substance both pointwise and over an area with the construction of element distribution maps. In the paper we investigated the influence of long-term and rapid heat treatments on the formation of the aluminum-polysilicon interface in order to study the formation of ohmic contacts in the element base of integrated circuits. The aluminumpolysilicon interface was studied using energy-dispersive X-ray microanalysis. It has been established that during long-term thermal annealing (450 °C, 20 min) polysilicon is completely dissolved in aluminum followed by its segregation in the form of separate agglomerates in the aluminum film, which can lead to a complete failure of the integrated circuit. During rapid thermal annealing (450 °C, 7 s) such a phenomenon was not detected. Thus it is advisable to use rapid thermal annealing as an alternative to traditional long-term thermal annealing in microelectronics. This makes it possible to significantly reduce the dissolution of polysilicon in aluminum, avoid the destruction of ohmic contacts and increase the percentage of yield of workable 0products in the process of integrated circuits' manufacturing.

Mixing oat proteins with lentil or faba bean proteins: How is the techno-functional behavior of the different protein systems affected by heat treatments?

Despite the growing market for plant-based products, rarely a single plant protein source manages to provide all the essential amino acids in a balanced way. Mixed protein systems combining proteins from more than one plant source may be useful to overcome this drawback. However, the mixture of proteins from different plant sources may impact the technological performance of the system. In this context, the influence of heat treatments of 75 and 95 °C for 15 min at neutral pH on the colloidal and the techno-functional properties of mixtures of protein isolates from lentil and oat (LO) and from faba bean and oat (FO) were investigated. The applied heat treatments induced subtle changes in the colloidal properties of the different systems. It was evidenced by size exclusion chromatography that oat proteins were more prone to heat induced changes than lentil or faba bean proteins. Regarding the techno-functional properties, mixing the proteins from the different sources had an antagonistic effect on foamability. On the other hand, an additive effect was observed for emulsifying capacities, with legume proteins displaying values between 93 and 100%, oat proteins close to 65%, and mixed systems between 78 and 93 %. Vicilin (7S) and β-basic subunits of legumin (11S) from lentil and faba bean, and oat 12S globulin were the main protein fractions stabilizing the interface of the obtained emulsions. The proteins from both sources coexisted at the interface of the emulsions stabilized by the mixed systems. The microstructure of the thermo-induced gels was dictated by oat proteins. However, the different legumes played a determining role in the critical gelling concentration measured (8 % w/w and 11.5 % w/w respectively for LO and FO). Mixing oat proteins with lentil or faba bean proteins allows modulating the techno-functional performance of the systems, thus represents an opportunity for innovative applications.

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.

Using Mössbauer Spectroscopy to Evaluate the Influence of Heat Treatment on the Surface Characteristics of Additive Manufactured 316L Stainless Steel.

The oxidation behaviour of iron-based 316L stainless steel was investigated in the temperature range of 700 to 1000 °C. The test specimens in the shape of plates were produced by selective laser melting. After fabrication, the samples were sandblasted and then annealed in air for different periods of time (0.5, 2, 8, 32 h). Under the influence of temperature and time, stainless steels tend to form an oxide layer. Scanning electron microscopy, energy dispersive analysis, and X-ray diffraction were employed to analyse the composition of this layer. Notably, a thin oxide layer primarily composed of (Fe-Cr) formed on the surface due to temperature effects. In addition, with increasing temperature (up to 1000 °C), the oxide of the main alloying elements, specifically Mn2(Fe-Cr)O4, appeared alongside the Fe-Cr oxide. Furthermore, the samples were subjected to conversion X-ray (CXMS) and conversion electron (CEMS) Mössbauer spectroscopy. CXMS revealed a singlet with a decreasing Mössbauer effect based on the surface metal oxide thickness. CEMS revealed the presence of Fe3+ in the surface layer (0.3 µm). Moreover, an interesting phenomenon occurred at higher temperature levels due to the inhomogeneously thick surface metal oxide layer and the tangential direction of the Mössbauer radiation towards the electron detector.

Fatigue response of AlSi10Mg by laser powder bed fusion: influence of build orientation, heat, and surface treatments

AbstractThe aim of this study is to analyze how the fatigue behavior of AlSi10Mg by laser powder bed fusion is affected by build orientation, heat, and surface treatments. A three-by-three factorial plan has been arranged for this purpose. Particularly, regarding the heat treatment, three levels were considered (as built, age hardening, and stress relief); whereas, for the surface treatment, three levels were investigated (micro-shot-peening, micro-shot-peening plus fine blasting, and machining and lapping following laser powder bed fusion). Regarding the build orientation, the specimens were manufactured using three different build orientations (0°, 45°, and 90°). The obtained data have been statistically analyzed by a three-factor ANOVA-based method. The results, supported by fractographic and micrographic microscopy analyses, indicate that the age-hardening treatment yields the maximum benefits, whereas stress relief may even have a detrimental effect. As for surface treatments, a positive influence of shot-peening has been found.

Coupling effect of post-weld heat treatment and fatigue damage on the hydrogen embrittlement of X80 steel welded joints

The influence of post-weld heat treatment (PWHT) and fatigue damage on the hydrogen embrittlement sensitivity of X80 steel welded joints, obtained using flux-cored arc welding method, was investigated in the study. Compared to the as-welded specimens, the sensitivity of hydrogen embrittlement after PWHT was decreased. However, the coupling effect of PWHT and fatigue damage improved significantly the HE sensitivity. Furthermore, the fracture site of the PWHT + pre-fatigue specimens with hydrogen-charged was transferred to the weld metal, and the fracture was characterized by intergranular fracture, quasi-cleavage (QC) and shallow dimples ductile fracture. The increase of the hydrogen content might be attributed to the evolutions of dislocation and the proportion of high-angle grain boundary caused by fatigue damage. Meanwhile, the size of QC for the hydrogen-charged welded joints was related to the degree of fatigue damage, hydrogen content and microstructure strength.

Influence of rapid heat treatment on the photocatalytic activity and stability of calcium titanates against a broad range of pollutants

Calcium titanate (CTO) photocatalysts were synthesized using a sol–gel method by adopting a cost-efficient, rapid calcination technique. The CTOs were characterized by X-ray diffractometry, X-ray photoelectron spectroscopy, infrared spectroscopy, nitrogen adsorption, porosimetry measurements, scanning/transmission electron microscopy, and diffuse reflectance spectroscopy. Their photocatalytic activity was assessed through the photocatalytic degradation of phenol, oxalic acid, and chlorophenol under UV light exposure, using a commercial CTO as a reference. The stability of the samples was evaluated using compounds with –OH, –COOH, and –Cl functional groups. Characterization results showed that CTO composites containing anatase, rutile, and brookite titania were obtained. Increasing the calcination temperature led to various crystalline compositions, higher crystallinity, larger primary crystallite sizes, and smaller specific surface areas. The photocatalytic activity of all CTO/TiO2 composites was superior compared to the commercial CTO we used as a reference. The high photocatalytic activity of the best-performing composites was attributed to their higher specific surface areas and the synergistic effect between the crystal phases. A cost comparison was also made between our unique calcination technique and conventional calcination, and it was found that our method is approximately 35% more cost-effective, while retaining the photocatalytic activity.

Influence of heat treatment on the structure and properties of Ti‒28Al‒7Nb‒2Mo‒2Cr titanium aluminide and its welded joints

Influence of heat treatment on the structure and properties of Ti‒28Al‒7Nb‒2Mo‒2Cr titanium aluminide and its welded joints

Вплив термічної обробки на структуру і властивості алюмініду титану TI–28Al–7Nb–2Mo–2Cr та його зварних з’єднань

Вплив термічної обробки на структуру і властивості алюмініду титану TI–28Al–7Nb–2Mo–2Cr та його зварних з’єднань

Hierarchically heterogeneous microstructure and mechanical properties in laser-directed energy deposition of γ-TiAl alloy through intrinsic cyclic heat treatment

The complex thermal effects of laser direct energy deposition (L-DED) provide significant advantages for production of high-performance γ-TiAl alloy, whereas challenges still exist in microstructure tailoring and mechanical properties. This work focuses on the influence of intrinsic cyclic heat treatment (ICHT) on the evolution of microstructures and mechanical properties in different building height regions of an L-DED TiAl alloy thin-wall sample. The results indicate that ICHT induces discontinuous coarsening (DC) effects by consuming the lamellar interface energy of the initial lamellae, resulting in grain refinement. With the increase in building height, the thermal accumulation leads to an increase in the initial lamellar spacing, which weakens the DC effect. At the top, insufficient thermal cycles prevent fine grain growth and erode coarse grains, hindering overall grain refinement. Ultimately, the hierarchically heterogeneous microstructure forms in the L-DED TiAl alloy, including refinement of hierarchical lamellar colony structure decorated with fine (α2+γ) lamellar structure and (α2+6H-LPS) lamellar structure (6H-LPS refers to 6H long-period structure phase). Specifically, the bottom region exhibits the best combination of ultimate tensile strength (706 ± 33 MPa) and strain (0.68 ± 0.05 %). The high tensile strength can be attributed to the hindrance of dislocation movement by the fine lamellae and the 6H-LPS phase ,caused by the high cooling rate of L-DED, while the elongation is attributed to the reduction in crack propagation energy due to the presence of fine grains.

Iodine enriched kale (Brassica oleracea var. sabellica L.)—The influence of heat treatments on its iodine content, basic composition and antioxidative properties

Iodine enriched kale (Brassica oleracea var. sabellica L.)—The influence of heat treatments on its iodine content, basic composition and antioxidative properties

Effects of cooling rate upon annealing on the microstructure and properties of the FeCo49V2Nb0.2 alloy

In this paper, the influence of heat treatment on the magnetic properties of permendur the FeCo49V2Nb0.2 alloy used as the rotor core of a generator is investigated. The as-cast alloy is forged, hot and cold rolled to a thickness of 0.2 mm. The alloy samples were annealed in an argon gas furnace at different cooling rates. The results of measuring properties using the vibrating sample magnetometer method and measuring hardness show that the cooling rate has a significant impact on the properties of the FeCo49V2Nb0.2 alloy. Combining X-ray diffraction analysis and microstructure analysis allows us to explain the changes in properties obtained. From the results obtained, a conclusion can be drawn about the appropriate cooling rate for this alloy to achieve the best magnetic properties.