Effect Of Aging Heat Treatment Research Articles

The evaluation of the aging process in 15-5 PH materials in terms of formability and microstructure

In this study, the effects of aging heat treatment of 15-5 PH stainless steel material on the mechanical properties, microstructure, and formability were investigated. Instead of cooling in air, cooling in the oven spontaneously was applied in the oven for the first time. Experimental studies show that aging heat treatment was applied for H900, H1025, and H1150 conditions at temperatures of 482 °C, 552 °C, and 621 °C, respectively, and 60 min for H900 and 240 min for H1025 and H1150. It has been observed that controlled cooling in the oven increases the mechanical values of the material obtained by cooling in the air by 8%–10%. The microstructures of the conditions after heat treatment were also examined, and it was observed that the cooling aging heat treatment in the oven caused precipitation hardening in the microstructure of the material. In addition, when evaluating the formability of the results using V-bending, it was observed that materials which could not withstand bending beyond 75° in Condition A (Con A), the initial state of the material, were smoothly shaped in all conditions and at all angles as a result of the cooling process in the oven. A decrease in spring-back angles has been detected due to the decrease in mechanical properties caused by increasing aging temperature. The highest spring-back value was also observed on a 75° bending die with 10.948° in the H900 condition which has the highest mechanical properties.

The Effect of Aging Heat Treatments on Room and High-Temperature Wear Performance of the Inconel 718™ Manufactured by Laser Powder Bed Fusion

The Effect of Aging Heat Treatments on Room and High-Temperature Wear Performance of the Inconel 718™ Manufactured by Laser Powder Bed Fusion

Effects of aging heat treatment on the mechanical properties of NiTi triply periodic minimal surface

This study investigated the impact of aging heat treatment time on the mechanical properties of NiTi triply periodic minimal surface structures fabricated through laser powder bed fusion. X-ray diffraction analysis results indicate that with increasing aging time, the NiTi2 phase precipitates while the content of the B19’ phase decreases. At 10 h of aging time, the Ni4Ti3 phase becomes evident in the sample. The differential scanning calorimeter results show that R phase transformation occurs, and the phase transformation temperature increases when the aging time reaches 6 h. Microhardness increases with aging time, peaking at 477.8 HV after 10 h. Compression experiment results reveal a maximum elastic modulus of 1262.82 MPa for the gyroid sheet-shaped structure achieved after 2 h. In addition, the superelasticity test indicates the highest recoverable strains at 2%, 4%, and 6% compressive strain for the gyroid rod-shaped structure after aging for 10 h. In cyclic compression experiments, the ratio of shape memory recovery increases from 40% at 0 h to 97% at 6 h. Fracture analysis results show that the transition in the fracture mechanism from brittle fracture to quasi-cleavage fracture occurs after aging heat treatment.

Effect of Aging Heat Treatment on Microstructure and Properties of Al–Cu–Mg Alloy

Effect of Aging Heat Treatment on Microstructure and Properties of Al–Cu–Mg Alloy

Effect of Aging Heat Treatment in an Al-4008 Produced by Liquid Metal Printing

In today's world, additive manufacturing (AM) is one of the most popular technologies and has the potential to revolutionize the manufacturing industry. As one of the most recent advances in this industry, liquid metal printing has a growing value in the engineering field. This study aims to evaluate the effect of two heat treatment conditions in an Al-4008 alloy produced by this technique in the microstructure and mechanical properties. It was concluded that the heat treatment (HT) enhances the Si particle coalescence and Fe-rich intermetallic compound precipitation, increasing the sample hardness significantly (50%). Density analysis showed a slight porosity decrease with HT. Tensile tests indicated heat-treated, same-directionally pulled samples exhibited brittleness compared to as-printed ones, while HT increased both yield strength (245 MPa) and ultimate tensile strength (294 MPa).

Effect of aging heat treatment on microbiologically influenced corrosion of 17–4PH stainless steel by Pseudomonas aeruginosa

The effect of aging heat treatment on the microbiologically influenced corrosion (MIC) of 17–4PH stainless steel by Pseudomonas aeruginosa was investigated. The presence of P. aeruginosa promoted the pitting corrosion of 17–4PH stainless steel. With the increase of aging temperature from 480 ℃ to 780 ℃, the corrosion resistance of the steel under inoculated conditions increased first and then decreased, achieving the best performance after 620 ℃ aging treatment. The heat-treated samples exhibited more uniform microstructure with fewer defects and more precipitated Cu-rich phase, which helped to improve the resistance of 17–4PH stainless steel to MIC.

Investigation of the effects of aging heat treatments on the mechanical and natural frequency properties of Al alloys

Investigation of the effects of aging heat treatments on the mechanical and natural frequency properties of Al alloys

The effect of aging heat treatment on the formability and microstructure of the AA6063 tube in the rotary draw bending process

This research delves into the impact of aging heat treatment on both the formability and microstructural characteristics of 6063 aluminum tubes when subjected to the rotary draw bending (RDB) procedure. To ascertain a heat treatment regimen that can yield desirable hardness and formability for the bending process, the tube was subjected to T3, T6, and annealing heat treatment cycles under diverse conditions and subsequently the tube's bendability was evaluated. The findings indicate that as temperature and dissolution time are raised, there is a corresponding rise in the extent of elliptical deformation, consequently resulting in higher hardness values. The research outcomes suggest that elevating both temperature and dissolution time leads to a more pronounced elliptical shape in the bent sample. For instance, when subjected to heat treatment at 530 °C and 545 °C for 60 min, the samples exhibited respective increases in ellipticity of 5.30 % and 4.34 % compared to those treated for just 30 min. Additionally, higher internal pressure led to a reduction in the degree of elliptical deformation, notably a decrease of 9.85 % observed at a pressure of 20 bar. Moreover, the hardness of samples subjected to the T3 cycle exhibited an upward trend with increasing both temperature and duration of heat treatment. To elaborate, the hardness measurements were conducted at three distinct temperatures (530 °C, 545 °C, and 560 °C) and four different durations (30, 45, 60, and 75 min). The sample subjected to a 75-minute heat treatment at 560 °C exhibited the highest recorded hardness value, measuring at 62.55 HV. In summary, the results indicate that aging heat treatment can enhance the formability of 6063 aluminum tubes during the RDB process. Furthermore, it is noteworthy that temperature and internal pressure serve as crucial parameters to control in order to mitigate elliptical deformation and enhance hardness.

Effects of aging heat treatment on microstructure and corrosion behavior of friction surfacing treated Al–Zn–Mg–Cu matrix composite

The effect of artificial aging heat treatment on the microstructure and corrosion behavior of Al–Zn–Mg–Cu matrix composite was studied. Nickel-aluminide reinforcement was fabricated in-situ during the stir casting process of Al–Zn–Mg–Cu alloy. After friction surfacing of the consumable rod of an as-cast composite on AA1050 substrate and post-processing artificial aging heat treatment at 125 °C for 18 h, significant grain growth was observed in the nickel-free sample. Moreover, the presence of nickel-aluminide reinforcement in the microstructure of composite resulted in the formation of bimodal microstructure. The presence of nickel-rich particles and the strengthening mechanism through precipitates could help increase the hardness and strength in the nickel-containing sample. After artificial aging heat treatment, the shear strength and hardness of composite containing nickel-aluminide increased by 24% and 13%, respectively, more than those of the aluminum matrix. Before aging heat treatment, the pitting corrosion resistance was significantly improved by the presence of nickel-containing particles. After aging heat treatment due to the adsorption of more significant amount of soluble copper by nickel-rich particles in the nickel-containing sample, corrosion resistance decreased by 39% compared to that of the nickel-free sample.

Effect of Aging Heat Treatment on Mechanical and Metallurgical Properties of Al2024 Reinforced with B4C/SiC/TiC Hybrid Composites Produced by Vacuum Infiltration Method

Effect of Aging Heat Treatment on Mechanical and Metallurgical Properties of Al2024 Reinforced with B4C/SiC/TiC Hybrid Composites Produced by Vacuum Infiltration Method

Evolution on the Microstructure and Mechanical Properties of a New Multicomponent Near-Alpha Titanium Alloy after Rolling and Heat Treatments

Near-alpha titanium alloys are widely used in aeroengine blades due to their excellent specific strength and mechanical properties. The mechanical properties of near-α titanium alloys are closely related to the evolution of the microstructure and precipitates. In this paper, the microstructure and mechanical properties of a new type of multi-component near-α titanium alloy sheet after rolling, 700 °C aging, and 800 °C aging were studied. The results show that the strength of the alloy after aging at 700 °C increases from 1156 MPa to 1304 MPa, respectively, but decreases to 1246 MPa with the aging temperature increasing. The ductility of the alloy aged at 700 °C is lower than that of the rolled state, but the ductility increases slightly with the aging temperature increasing. The effect of aging heat treatment on the microstructure and precipitation behavior of alloy plates has been studied and compared with alloys before aging. After heat treatment, the content of primary α decreases from 25% to 5%, respectively. Two kinds of silicide precipitate at different positions, with the large-size spherical silicide being (Ti, Zr, Nb)5Si3, and the small-size fusiform silicide being (Ti, Zr, Nb)6Si3, respectively. Ti3Al was precipitated in the primary α phase, during the aging process. The silicides exhibit the strengthening effect on the alloy, but the effect weakens when the silicides grow up. The loss in ductility is mainly attributed to the precipitation of the α2 phase after aging treatment. However, ductility is improved after applying higher aging temperatures as the size of the α2 phase becomes smaller, and the distribution of them tends to become dispersed.

Effect of Aging Heat Treatment on Wear Behavior and Microstructure Characterization of Newly Developed Al7075+Ti Alloys.

In this study, Al7075+0%Ti-, Al7075+2%Ti-, Al7075+4%Ti-, and Al7075+8%Ti-reinforced alloys were prepared by melting processes using Al7075 and Al-10%Ti main alloys. All newly produced alloys were subjected to T6 aging heat treatment and some samples were cold rolled at 5% beforehand. The microstructure, mechanical behavior, and dry-wear behavior of the new alloys were examined. Dry-wear tests of all alloys were carried out at a total sliding distance of 1000 m, at a sliding speed of 0.1 m/s, and under a load of 20 N. In the hardness measured after T6 aging heat treatment, the peak hardness of the Al7075+0%Ti-, Al7075+2%Ti-, Al7075+4%Ti-, and Al7075+8%Ti-reinforced alloys was found to be 105.63, 113.60, 122.44, and 140.41 HB, respectively. The secondary phases formed by the addition of Ti to the Al7075 alloy acted as precipitate-nucleation sites during aging heat treatment, further increasing the peak hardness. Compared to the peak hardness of the unrolled Al7075+0%Ti alloy, the increase in the peak hardness of the unrolled and rolled Al7075+8%Ti-reinforced alloys was 34% and 47%, respectively, and this difference in the increase was due to the change in the dislocation density with cold deformation. According to the dry-wear test results, the wear resistance of the Al7075 alloy increased by 108.5% with a reinforcement of 8% Ti. This result can be attributed to the formation of Al, Mg, and Ti-based oxide films during wear, as well as the precipitation hardening, the secondary hardening with acicular and spherical Al3Ti phases, the grain refinement, and solid-solution-hardening mechanisms.

Enhanced strengthening effect of aging heat treatment found in additively-formed CoCrFeNiTi-based multiprincipal element alloy

The strengthening effect caused by the fine precipitation in microcellular structures during aging heat treatment (AHT) in CoCrFeNiTi-based multiprincipal element alloys fabricated using laser-powder bed fusion (L-PBF) was investigated. L-PBF fabricated products after AHT at 923–1173 K demonstrated hardness of 692 HV, and ultimate tensile strength of 1824 MPa, whereas solution heat-treated products exhibited a hardness of 530 HV and ultimate tensile strength of 1562 MPa. X-ray diffraction, scanning electron microscopy, and scanning transmission electron microscopy demonstrated the presence of intermetallic compounds in the microcellular structures formed during L-PBF solidification. Microcellular structures in as-built specimens accompany dislocation networks and elemental segregation around microcellular walls. The hierarchical structure increases the strengthening effect of AHT by forming a large number of fine multiple intermetallic compounds. AHT after solution heat treatment causes the growth of strengthening nanoscale precipitates in equiaxed grains with a lower amount of grain boundary precipitates. The different responses to AHT in specimens with and without solution heat treatment are important issues for controlling the properties of additively manufactured products.

Changes in thermal properties of 7075 aluminium alloy by aging heat treatment

This study investigated the effects of aging heat treatment on the change of thermal properties of 7075 Al alloy using differential scanning calorimetry and a laser flash apparatus. The thermal diffusivity showed different trends in the three temperature ranges: In the range from room temperature to 160°C, the thermal diffusivity increased with increasing temperature. Between 160 and 240°C, the thermal diffusivity increased with an increase in the temperature of the specimen. Precipitation was completed at 240°C or higher, and the thermal diffusivity decreased with an increase in the temperature of the specimen. The amount of precipitation of η′ and η phases did not affect the change in thermal diffusivity but only contributed to the improvement of micro-hardness.

Microstructure, Tensile, and Fatigue Properties of Large-Scale Austenitic Lightweight Steel.

High-Mn lightweight steel, Fe-0.9C-29Mn-8Al, was manufactured using steelmaking, ingot-making, forging, and rolling processes. After the final rolling process, a typical austenite single phase was observed on all sides of the thick plate. The microstructural changes after annealing and aging heat-treatments were observed, using optical and transmission electron microscopy. The annealed coupon exhibited a typical austenite single phase, including annealing twins in several grains; the average grain size was 153 μm. After aging heat treatment, κ-carbide was observed within the grains and on the grain boundaries. Additionally, the effect of aging heat treatment on the mechanical properties was analyzed, using a tensile test. The fine κ-carbide that precipitated within the grains in the aged coupon improved the 0.2% offset yield and the tensile stresses, as compared to the as-annealed coupon. To estimate the applicability of high-Mn lightweight steel for low-pressure (LP) steam turbine blades, a low-cycle fatigue (LCF) test was carried out at room temperature. At a total strain amplitude of 0.5 to 1.2%, the LCF life of high-Mn lightweight steel was approximately three times that of 12% Cr steel, which is used in commercial LP steam turbine blades. The LCF behavior of high-Mn lightweight steel followed the Coffin-Manson equation. The LCF life enhancement in the high-Mn lightweight steel results from the planar dislocation gliding behavior.

Quantitative kinetic analysis of γ′ precipitate evolution in a Co–Al–W superalloy during aging heat treatment

In this research, the effect of aging-heat treatment on evolution of γ′-precipitates in the Co–Al–W-based superalloy was studied. For this purpose, solution heat treatment was applied followed by water-quenching and then, aging different cycles were carried out at four temperatures of 720, 780, 840 and 900 °C for different holding time (1–48 h). The electron microscope micrographs showed that increasing size of γ′ particles happens with more holding time; while volume fraction stays approximately constant at 0.72. In addition, the γ-γ′ lattice mismatch, as positive values, increased with holding time increase due to simultaneous γ′ shape adaptation. While the γ′ morphology variation was seen to change from spherical to semi-cubic and cubic; the L- and stretched-shapes of γ′-particles with concurrent split of the coarse particles was detected by coarsening, coalescence and splitting phenomena, respectively. The proposed mechanisms for such microstructural evolution were interpreted based on n value as the power term in kinetics equation. As such, the γ′-particles diffusion across the γ/γ′ interface (n∼2), volume-diffusion (n∼3) and coalescence/splitting (n∼7) are key controlled processes at different aging temperature ranges. The characteristics of γ′-precipitates was discussed in detail based on total energy concept in terms of surface (Esur.), elastic strain (Estr..) and interactions of elastic (Eint.) energies and hence, a phenomenological model was proposed for evolution of γ′-particles. Modeling based a physical model and analysis of microhardness experimental revealed that the desired radius of γ′ phase should be between 80 nm and 90 nm respectively; and the optimized aging condition is estimated to be done at 840 °C for 36 h.

Effect of aging heat treatment on microstructure of Ni-based single crystal superalloys

The precipitation and evolution of γ′ precipitates for various aging heat treatment regimes are studied experimentally in Ni-based single crystal superalloys for both standard heat treatment and long-term aging samples. The focus of this paper is to explore the influence of aging heat treatment on the evolution of the morphology and the distribution of γ′ precipitates. It is demonstrated that the splitting and shrinkage phenomena appear at low aging heat treatment temperatures, and the passivation phenomenon occurs at a high aging temperature of 1200°C. The uniform cubic γ′ particles can be obtained at 1100°C/4 h for the standard heat treatment samples and 1150°C/8 h for the long-term aging ones. This research is beneficial for the study of the rejuvenation aging heat treatment in re-service nickel-based superalloys.

Effect of Aging Heat Treatment on Compressive Characteristics of Bimodal Aluminum Syntactic Foams Produced by Cold Chamber Die Casting

Effect of Aging Heat Treatment on Compressive Characteristics of Bimodal Aluminum Syntactic Foams Produced by Cold Chamber Die Casting

Effect of Aging Heat Treatment on Corrosion Behavior and Corrosion Kinetics of 17-4PH Stainless Steel in Artificial Saliva

The corrosion behavior of the sintered 17-4PH stainless steel samples aged at different conditions in artificial saliva was studied using the method of electrochemical and weight loss after exposure for various periods of time. The results showed that the samples aged at 480 °C for 1 h exhibited the highest corrosion resistance.The pitting corrosion was predominantly initiated from existing, isolated pores and further accelerated. The corrosion kinetics trend is found to be more consistent with a bimodal function form rather than the classical power-law function.

Effect of Aging Heat Treatment at 400-600°C on the Microstructure and Tensile Properties of 15Cr-15Ni Ti-Stabilized Steel Cladding

This study investigates the effect of thermal aging on the microstructure and tensile properties of a 15-15Ti austenitic stainless steel in the baseline operating conditions of a sodium fast reactor, in the range between 400°C and 600°C. Samples that were aged at up to 600°C for 1000 hours exhibit no evidence of material recovery. Thus, after aging heat treatments, micro-hardness measurements do not decrease, and TEM analyses do not show any modification of the dislocation network. However, TEM examinations have indicated a new threshold for the precipitation of nanometric titanium carbides after an isothermal treatment at 500°C for about 5000 hours. Concerning the tensile properties, the aged states present a gain both in strength and in ductility compared to the initial cold-worked state. The large gain in ductility is observed for all of the temperatures tested (between 20°C and 400°C) and occurs concomitantly with an increase in the strain hardening rate of the material. One plausible hypothesis to explain this improvement of the mechanical behaviour relies on the nanometric titanium carbides formed during the aging process. These precipitates could act as obstacles that impede the motion of existing dislocations, thereby contributing an additional strain hardening mechanism, which would lead to greater strength and also delay the onset of strain localization.