Effect Of Aging Temperature Research Articles

Effect of aging temperature on the redrawn cup wall of a novel Cu-0.5Cr-0.05Zr-0.05Ti (wt.%) alloy sheet: Analyses on microstructure evolution, mechanical properties and strengthening mechanism

A solution-treated Cu-0.5Cr-0.05Zr-0.05Ti (wt.%) alloy was drawn into a large-depth cup implementing a two-stage deformation process in the present study, firstly using a ∅50 mm cylindrical punch and subsequently redrawn by a ∅34 mm punch. The redrawn cup wall was subjected to aging heat treatment up to 400 °C, 500 °C, and 600 °C for 2 h followed by water quenching to understand the microstructural evolution and its correlation with mechanical properties. These aging temperatures were adopted to simulate a similar environmental condition in which the inner liner of the thrust chamber of cryogenic and semi-cryogenic engines was exposed during satellite launching. It was identified that the above aging temperatures influenced the grain characteristics, recrystallization, and annealing twin formation significantly. The redrawn cup wall possessed semi-coherent bcc spherical Cr-rich precipitates with an average size of 1.8 ± 0.1 nm, which progressively increased to 5.5 ± 0.3 nm at 600 °C, while the precipitate volume fraction increased to a maximum of 1.2% at 500 °C. The precipitation mostly influenced the strength, while the recrystallization and twin formation governed the ductility during the aging. After an initial decrement at 400 °C, the yield strength of the aged specimen was increased to a maximum of 193 MPa with a concurrent increase in ductility to 24% upon the optimal aging at 500 °C. However, a higher increment in the strength than the ductility indicated the dominance of the precipitation. Further increase in the temperature to 600 °C reduced the strength while considerably enhancing the ductility. This was attributed to the highest recrystallization and twin fraction, as well as precipitate coarsening with reduced volume fraction. Moreover, precipitation strengthening prevailed in the aged specimens, unlike dislocation strengthening in the redrawn condition. The contribution from the former was maximum at 500 °C with a 52% share of the total estimated strength, whereas it was only 31% in the redrawn specimen.

Effect of aging temperature on microstructure and mechanical properties of (Ti1400+TiC)/Ti6Al4V composites

Titanium matrix composites, due to their high strength, high modulus, and high temperature resistance, have become ideal materials that meet the lightweight and high-performance requirements in the aerospace industry. However, their poor ductility remains a key issue that restricts their widespread application. In this study, (Ti1400+TiC)/TC4 composites were prepared by low-energy ball milling and spark plasma sintering and subjected to solution treatment and aging treatment. The effects of aging temperature on the composition, microstructure, and mechanical properties of the composites were analyzed, and the strengthening mechanism of (Ti1400+TiC)/TC4 composites was discussed. The aging temperature between 350 ℃ and 700 ℃ had little effect on the microstructure of TC4 matrix and the discontinuous three-dimensional network structure of TiC particles. As the aging temperature increased, the elongated α-phase within the Ti1400 region became shorter and thicker, and Cr’s rapid diffusion resulted in β-phase being more widely distributed. After aging at 600 ℃, the tensile strength of the composite was 1202 MPa, and its total elongation reached 11.3 %, showing excellent strength-plasticity matching. The mechanical properties of composites are mainly affected by the microstructure in the Ti1400 region. The elongated α-phase in the Ti1400 region provides high strength for the composite. The thicker α-phase and the widely distributed β-phase led to more uniform strain within the composite, avoiding premature fracture caused by stress concentration near TiC particles and promoting ductility in the composite.

Effect of aging temperatures on the microstructure and mechanical properties of TC21 forgings with basket–weave microstructure

This study aims to explore the influence of various aging temperatures on the microstructure and mechanical properties of TC21 forgings. Basket-weave microstructures were prepared via quasi-β forging followed by annealed at 900 °C for 1.5 h and aged at 530 °C, 560 °C, and 590 °C for 4 h, and then their tensile performance, impact toughness, and fracture toughness were examined. Results indicate that higher aging temperatures not only facilitate the segregation of Al element, resulting in a reduction in the effective size (dαlaths, the width/length ratio) of primary α laths (αlaths) and their amount, but also promote phase transition, inducing an increase in the effective size (dαfine) of secondary fine α (αfine) lamellae. While both dαlaths−1/2 and dαfine−1/2 have a linear relationship with the strength, which was analyzed using the Hall–Petch relationship, the more pronounced interface strengthening effect and hindering crack propagation mainly results from the αlaths. Moreover, the plasticity declines significantly as the proportion of the αlaths phases decreases. Thus, for strength and plasticity, the αlaths are a much more important factor than the αfine lamellae. However, although the synergistic deformation and fracture of both the αlaths and αfine phases can consume a larger impact initiation energy, the enhancement of the impact energy of the alloy is primarily related to a high precipitation amount of the αfine lamellae. Furthermore, the decrease in dαlaths promotes the misorientation and accumulation of dislocations between αlaths interfaces, hindering the enhancement of KIC (fracture toughness) by forming transgranular fractures. Conversely, the increase in KIC attributed to the energy consumed in the plastic deformation region at the crack tip, due to the αfine lamellae compensates for the energy, resulting in a reduction in the crack propagation path. Therefore, the αfine lamellae may play a more crucial role in increasing the toughness of alloys, in particular the impact toughness of the TC21 alloy.

Effect of aging temperature on the microstructure and properties of alloyed high‐manganese steel

Effect of aging temperature on the microstructure and properties of alloyed high‐manganese steel

Effect of aging temperature on the lubricated wear resistance of multi-directionally forged Al-40Zn-3Cu alloy

The effect of aging temperature on the lubricated wear behavior of multi directionally forged Al-40Zn-3Cu alloy was systematically investigated at different loads and sliding speeds. Microstructural and worn surface examinations of the alloy samples were performed by scanning electron microscopy, scanning transmission electron microscopy and energy dispersive spectrometry while their tribological properties were investigated with a ball on disc type wear test apparatus. The results showed that aging treatment at different temperatures after multi-directional forging changed the morphology of Zn-rich nanoscale η precipitates and Cu-rich θ particles and their dispersion in α-Al matrix. Their changes brought about an increase in hardness, strength, and wear resistance of Al-40Zn-3Cu alloy but a decrease in its ductility. It was also observed that the aging temperature, load and sliding speed had a combined effect on their wear response. As the applied load and sliding speed increased, friction coefficient of the samples decreased while their mass loss increased continuously with load but decreased with sliding speed after showing an increase. The adhesion, abrasion and oxidation were observed to be operative wear mechanisms for the alloy. The wear results of the alloy samples were discussed in terms of their microstructures and mechanical properties, and oil lubrication. The aging treatment at 150 °C after multi-directional forging increased the wear resistance of Al-40Zn-3Cu alloy more than 50 percent by providing a moderate hardness (129 HB), yield strength (310.9 MPa), tensile strength (383.2 MPa), and ductility (9.9 %).

Design and Rate Control of Large Titanium Alloy Springs for Aerospace Applications

During the separation between satellite and launch vehicles, large steel springs are often used as compression separation spring sets in a catapult separation system. Replacing the steel springs with titanium alloy springs could reduce weight by about 50%. Although titanium alloy springs have been widely used in the aerospace field due to their excellent performance, there are few reports on the design of high-precision titanium alloy springs. The current spring design standards mainly focus on steel springs with helix angles between 5° and 9°, which are not applicable to titanium springs. Moreover, the change in spring rate with ambient temperature should also be considered. In this paper, β-C titanium alloy was used to design and prepare large compression separation springs, replacing steel springs in the catapult separation system. The design of titanium alloy springs took into account the big helix angle. The relationship between helix angle and the number of active coils was calculated. The parameters of titanium alloy springs were determined by the shear stress of the spring at working length. The effects of aging temperature and aging duration on the mechanical properties and modulus of β-C alloy were studied. By adjusting the aging process, the β-C alloy spring rate was controlled to meet the design requirements. The effect of ambient temperature on the mechanical properties and modulus of β-C titanium alloy were also investigated. It was found that as the ambient temperature increased, the rate of the β-C alloy spring gradually decreased.

Effect of aging temperature on microstructure and properties of cold-rolled Cu-Ni-Si alloy

The aging process plays a pivotal role in shaping the microstructure of Cu-Ni-Si alloys, a typical kind of precipitation-strengthened Cu alloy. This process significantly affects both the mechanical and electrical properties of the final Cu alloy strips. In this study, Cu-Ni-Si alloy sheets underwent a 90 % reduction through cold rolling at room temperature, followed by heat treatment at temperatures ranging from 400 to 650 ℃. A comprehensive investigation was conducted into how cold rolling deformation and the aging process affect the alloy's microstructure, as well as its mechanical and electrical properties. The analysis was performed using a scanning electron microscope equipped with a backscattered electron diffraction system (SEM-EBSD), complemented by transmission electron microscopy (TEM). The findings revealed that recrystallization and precipitation occurred concurrently and were both enhanced by higher temperatures and prolonged heat treatment durations. However, recrystallization at elevated temperatures has a marginal impact on enhancing electrical conductivity and results in a significant reduction of mechanical properties. In contrast, alloys preserving the deformed microstructure benefit from multiple strengthening mechanisms, including precipitation, dislocation, grain boundary, and texture strengthening. This study offers quantitative insights into the precipitation and recrystallization behaviors of Cu-Ni-Si alloys, contributing significantly to a deeper understanding of the mass production of high-performance copper alloys.

A Preliminary Study on the Effects of Aging Temperature on the Microstructure and Mechanical Properties of As-Extruded Mg-12Gd-4Y-1Zn Magnesium Alloy

A Preliminary Study on the Effects of Aging Temperature on the Microstructure and Mechanical Properties of As-Extruded Mg-12Gd-4Y-1Zn Magnesium Alloy

Effect of Aging Temperature on Secondary α Phase and Tensile Properties of Ti-5.5Cr-5Al-4Mo-3Nb-2Zr

Effect of Aging Temperature on Secondary α Phase and Tensile Properties of Ti-5.5Cr-5Al-4Mo-3Nb-2Zr

Effect of ageing temperature on the microstructural evolution and mechanical properties in M2C and NiAl co-precipitation secondary hardening ultrahigh-strength steel

A novel cost-effective secondary hardening ultrahigh-strength steel, strengthened by the co-precipitation of M2C and NiAl, was developed. The present study systematically investigated the co-precipitation evolution, austenite reversion, and mechanisms of strengthening and toughening at different ageing temperatures. As the ageing temperature increased, the quenched microstructure underwent various transformations, including precipitation and dissolution of cementite, nucleation and coarsening of M2C and NiAl nanoparticles, as well as reversion of austenite. At ageing temperatures of 427 °C and 454 °C, a small amount of cementite was present in the martensite matrix, and M2C and NiAl precipitates started to form, resulting in low strength and poor toughness. At 482 °C, the peak-ageing stage was reached, achieving a maximum yield strength of 1875 ± 4 MPa and an ultimate tensile strength of 2185 ± 3 MPa. This strength is primarily attributed to shear strengthening of NiAl particles and Orowan strengthening of M2C carbides. Additionally, the complete dissolution of cementite at this stage improved toughness. As the ageing temperature increased to 510 °C and 538 °C, the strength decreased due to coarsening of M2C, while the toughness improved as a result of film austenite reversion and enhanced dislocations bypassing around the M2C carbides.

Unravelling precipitation behavior and mechanical properties of Al–Zn–Mg–Cu alloy

We investigate the effect of aging temperature on precipitation behavior and mechanical properties of an Al–7.6Zn–2.7Mg–2.0Cu–0.1Zr–0.07Ti (wt.%) alloy by evaluating the matrix's microhardness, electrical resistivity, and tensile properties: additionally, employing X-ray diffraction (XRD), differential scanning calorimetry (DSC), transmission electron microscopy (TEM), and atom-probe tomography (APT) to characterize this alloy. The nanoprecipitates forming under peak-aging conditions vary with aging temperature, forming coherent GPI zones at 80 °C, GPII zones with minor η' at 120–150 °C, and η'/η with minor GP zones at 180–220 °C. GPI and GPII zones forming at 80–150 °C contain similar concentrations of solute atoms (11Zn–9Mg–(<1.0)Cu (at.%)), whereas the η'/η nanoprecipitates forming at 180 °C contain larger concentrations of solute atoms (28Zn–24Mg–3.4Cu (at.%)). The strength of the peak-aged alloy decreases with increasing aging temperature owing to the increasing size and decreasing number density of the nanoprecipitates. Under peak-aging conditions, precipitation strengthening originates mainly from dislocation shearing at 80–150 °C and from Orowan bypassing at temperatures above 180 °C. The shearable to non-shearable transition of the nanoprecipitates at 180 °C reduces the strain hardening rate, thereby decreasing the alloy's ductility.

Effect of Aging Temperature on Microstructure, Mechanical, and Wear Properties of 18Ni-300 Maraging Steel Produced by Powder Bed Fusion

Additive manufacturing technologies for metallic materials based on powder bed fusion have enormous industrial potential. In this study, we manufactured 18Ni-300 maraging steel using the powder bed fusion (PBF) process and investigated the effects of annealing temperatures of 430 °C, 490 °C, and 550 °C for 3 h on its microstructure, tensile fracture mechanism, and wear properties compared with the as-built specimen. The results show that annealing heat treatment effectively improved the dry sliding friction, wear properties, and room temperature tensile properties compared to the as-built specimen. Compared to other aging-treated samples, specimens that underwent heat treatment in optimal settings had superior properties. With optimal heat treatment, while melt pool boundaries remained, the cellular and columnar structures became finer compared to the un-treated specimens, and the number of dimples decreased. Consequently, the hardness and tensile strength improved by approximately 56.17% and 40.63%, respectively. The 18Ni-300 maraging steel sample that underwent heat treatment at optimal settings exhibited a coefficient of friction approximately 33.33% lower than the as-built alloy.

Effect of aging temperature on microstructure and softening property of the Cu-Cr-Zr-Nb alloy

The microstructure and properties of the aged Cu-Cr-Zr-Nb alloy were studied by means of hardness tester, universal tensile testing machine, conductivity meter, X-ray diffraction, scanning electron microscope, and transmission electron microscope. The results indicated that the hardness and TS (tensile strength) of the Cu-Cr-Zr-Nb alloy increased first and subsequently decreased with increasing the aging temperature. Nevertheless, the electrical conductivity is gradually increasing. The aged Cu-Cr-Zr-Nb alloy was mostly made up of Cu matrix, Cr particles, Cr2Nb, and CuZr compounds. Due to the effects of dislocations accumulated by cold drawing and twins produced during the aging process, the softening temperature of the alloy reached 590 ℃. When the Cu-Cr-Zr-Nb alloy was aged at 490 ℃, < 111 > replaced < 110 > in the optimal orientation of the alloy, and the KAM (kernel average misorientation) value inside the alloy was the largest. The alloy exhibited great comprehensive properties at 490 ℃ for 1 h, with a hardness of 144.4 HBW, a TS of 521 MPa, and an electrical conductivity of 78.3%IACS. The contribution value of YS (yield strength) at different aging temperatures was further calculated. The computational results showed that precipitation strengthening was the main strengthening mechanism of the Cu-Cr-Zr-Nb alloy, and fine-grained strengthening and dislocation strengthening simultaneously played a supplementary role.

Effect of Aging Temperature on Pitting Corrosion of AA6063 Aluminum Alloy

Effect of Aging Temperature on Pitting Corrosion of AA6063 Aluminum Alloy

Effects of aging temperature on microstructure and mechanical properties of PH 13-8Mo stainless steel

Precipitation hardening stainless steel (PHSS) possesses high strength, impact resistance, and corrosion resistance, making it extensively employed in aerospace, nuclear power equipment, and petrochemical industries. The precipitates and reversed austenite (RA) generated during heat treatment significantly influence the properties of PHSS. This study investigates the impact of aging temperature (480–620 °C) on PH 13-8Mo stainless steel. As the aging temperature increased from 480 °C to 620 °C, the yield strength (YS) and ultimate tensile strength (UTS) initially increased and then decreased, while the impact energy initially decreased and then increased. At an aging temperature of 510 °C, the strength and hardness reach their maximum values, indicating peak aging conditions. The microstructure after aging treatment is lath martensite, RA and NiAl. With increasing aging temperature, the size of NiAl precipitates increases, accompanied by a rise in RA content. The quantitative analysis assessed the contributions of various strengthening mechanisms (precipitation strengthening, solid solution strengthening, grain refinement strengthening, dislocation strengthening, etc.) to YS. Quantitative calculations revealed that the precipitation strengthening effect was most pronounced at an aging temperature of 510 °C.

Effect of aging temperature on microstructure and mechanical properties of Fe–Ni–Cr–Al high entropy alloy

Investigating the strength–plasticity synergy of metal structural materials is a crucial scientific challenge. This study focuses on preparing high-entropy alloys (HEAs) comprising Fe–Ni–Cr–Al, which exhibit a heterostructural coexistence of several phases through cold rolling and aging (CRA). Above 600 °C CRA, the average grain size of the HEA was refined from 260 to 1.64 μm, and numerous annealing twins were formed. Concurrently, two forms of irregularly ordered body-centred cubic (B2) phases and nanoscale ordered face-centred cubic (L12) phases were precipitated. Large B2 particles precipitated along the grain boundary, whereas small B2 and L12 particles precipitated within the grains. The average sizes of the B2 and L12 particles were 510 and 2.21 nm, respectively. The fine grain and precipitation strengthening enhanced the HEA yield strength (from 254 to 710 MPa). The difference in plastic strain between the matrix and precipitate causes long-range back-stress strengthening and heterodeformation-induced hardening, enhancing the strain-hardening ability and maintaining the superior plasticity of the HEA. This study provides an effective approach for obtaining metal structural materials with strength–plasticity synergy.

Heterogeneous effect of aging temperature on the fatigue life of additively manufactured thin-walled 18Ni300 maraging steel tubular specimen

Optimizing the geometry for material savings, or heat transfer, can yield thin-walled additively manufactured parts. A wall thickness of only a few hatching spaces can be fabricated using laser powder bed fusion (LPBF). However, the unmachined surface quality and subsurface defects in the low-thickness wall put the load-bearing capacity of the manufactured part under scrutiny. This study aimed to determine the fatigue and quasi-static strengths of nominally 0.5-mm thick tubular specimens of LPBF 18Ni300 maraging steel with respect to the aging temperature (AT). The experimental tests were conducted on six batches of unmachined specimens: non-aged and age-hardened for 6 h at different temperatures, i.e., 450, 470, 490, 530, and 585 °C. The void distribution and specimen surface were characterized using X-ray micro-computed tomography. The heterogeneous effect of AT on fatigue life was recognized by a novel application of the Gaussian process for regression. The mechanical properties of a 0.5-mm thick tubular specimen were equal to or higher than those of a full cross-section specimen. Furthermore, the optimal AT to obtain the highest fatigue strength was 520 °C for low-cycle fatigue, decreasing to 480 °C for high-cycle fatigue.

Effect of Aging Temperature on the Microstructure and Mechanical Properties of a Novel β Titanium Alloy

High-strength metastable β titanium alloys are promising structural materials to be used in aviation industries. In order to achieve a high strength level, solid solution treatment within β region and subsequent low-temperature aging are usually necessary to obtain fine α precipitates. The selection of the aging temperature is considered critical to the mechanical performance of metastable β titanium alloys. In this work, we investigated the effect of aging temperature on the microscopic structure and mechanical properties of a novel type of titanium alloy TB18 (Ti-4.5Al-5Mo-5V-6Cr-1Nb). A series of aging treatments were conducted on TB18 specimens at 510 °C, 520 °C, 530 °C, and 540 °C after the solid solution treatment at 870 °C. On the basis of the systematic results of scanning electron microscope and transmission electron microscope, the behavior of the α phases affected by the varied aging temperatures were studied. As the aging temperature rose, the grain width of the α phase increased from 60 nm (510 °C) to 140 nm (540 °C). For the TB18 samples aged at 510 °C and 540 °C, the tensile strength/yield strength/impact toughness values were 1365 ± 3 MPa/1260 ± 0.9 MPa/26.5 ± 1.2 J/cm2 and 1240 ± 0.9 MPa/1138 ± 0.8 MPa/36.2 ± 1.3 J/cm2, respectively. As a result, the tensile performance and the grain width of the α phase agreed well with the Hall–Petch relationship. This work offers valuable support for both theoretical analyses and the heat treatment strategies on the novel TB18 titanium alloy.

Effect of aging temperature on corrosion resistance of 316L stainless steel in simulated proton exchange membrane fuel cell cathode environment

The effects of aging temperature on the corrosion behavior of 316 L stainless steel in a simulated cathodic environment of a proton exchange membrane fuel cell (PEMFC) were investigated by potentiodynamic polarization curves, electrochemical impedance spectroscopy (EIS), double-loop electrochemical potential response (DL-EPR). The results show that the corrosion resistance of 316 L is significantly degraded after aging at 750–900 °C for 1 h in the simulated cathodic environment of PEMFC. A strong sensitivity to intergranular corrosion takes place after aging at 850 °C, and chromium rich M23C6 carbides precipitate on grain boundaries. The precipitation of M23C6 leads to discontinuity of the passivation film near the grain boundaries, resulting in Cr-depleted zones at the grain boundaries, increasing intergranular corrosion, and decreasing corrosion resistance. When the aging temperature exceeds 950 °C, grain boundary precipitation of M23C6 does not occur and the corrosion resistance is improved. At an aging temperature of 1050 °C, a dense Cr2O3 film is formed on the surface of the alloy during the polarization test, giving it the best corrosion resistance in the simulated cathodic environment of PEMFC.

Effect of Aging Temperature on Microstructure, Hardness and Thermal Property of AA7085 Alloy

Effect of Aging Temperature on Microstructure, Hardness and Thermal Property of AA7085 Alloy