Martensitic Structure Research Articles

Effect of moderate Fe doping and heat treatment on the microstructure of Ni-Mn-Ga melt-spun ribbons

The present work investigates the effects of Mn substitution with additions of Fe (0.5, 1, 2, and 3 at%) on the crystal structure, phase transformation temperatures, and magnetic properties of casted and heat-treated Ni49.8Mn28.5−xGa21.7Fex magnetic shape memory (MSM) alloys. The alloys doped with 0.5 and 1 at% Fe exhibited single-phase seven-layered modulated (14 M) and five-layered modulated (10 M) martensite structures at ambient temperature, whereas the alloys doped with 2 and 3 at% Fe exhibited L21 Heusler austenite structures at ambient temperature. The Ni49.8Mn27.5Ga21.7Fe1 alloy exhibiting the 10 M crystal structure at ambient temperature was selected for making ribbons using the melt-spinning process. The effects of heat treatment on grain growth, crystal structure, and other functional properties of the melt-spun ribbons were studied. The ribbons heat-treated at 1273 K exhibited a 10 M martensite structure and an average grain size of 220 µm along the ribbon plane. The results show that Ni49.8Mn27.5Ga21.7Fe1 is a particularly promising composition for designing and manufacturing functional MSM micro-actuators.

Effect of PWHT on metallurgical and mechanical characterization of dissimilar welded joint of P91 and P92 steels

P91 and P92 steels are widely used in nuclear and thermal power plant’s high-temperature (650–700 °C) operating components. The welding procedure, base plate composition, filler material composition, and post-weld heat treatment (PWHT) significantly affect the metallurgical characterization of weldments at room temperature. This work focuses on joining P91 and P92 steel by the TIG welding with filler ER90S-B9. The study analyzes the materialization of coarse-grained HAZ (CGHAZ), inter-critical HAZ (ICHAZ), and fine grained HAZ (FGHAZ) under welded and PWHT. PWHT was conducted at 840 °C for 2, 4 and 6h. An optical microscopic (OM) scanning electron microscope (SEM) was employed to characterize the welded and PWHT samples. It was perceived that the tensile strength of PWHT increased as the heat treatment times increased from 2 to 6 h, while the hardness value decreased accordingly. The maximum tensile strength (594.71 MPa) was observed in PWHT_6 h, while the minimum tensile strength (537.52 MPa) was perceived in the as-welded sample. The PWHT_6h reveals the minimum hardness values (271.12 HV) at the fusion zone among all the conditions. The WFZ consisted of an untampered lath martensitic grain structure, demonstrating an average hardness value of 314.15 HV in the PWHT_2h condition. The hardness value in CGHAZ samples for as-welded, PWHT_2h, PWHT_4h, and PWHT_6h was observed at 456.85, 436.81, 368.63, and 327.41 HV, respectively.

Enhancement of strength-ductility trade-off in a 2000 MPa grade press-hardened steel via refined martensite with stable high-density cementite

High-strength press-hardened steels (PHSs) are characterized by a martensite structure of high strength and adequate ductility. Strengthening PHSs with high C contents is usually accompanied by a loss of ductility and toughness. To overcome this inherent strength–ductility trade-off dilemma, we propose a novel strategy to achieve outstanding mechanical performance by introducing stable high-density Cr-rich cementite, which refines the martensite structure via Zenner pinning effect in a novel 2000 MPa grade PHS. Specifically, a high tensile strength of 2085 MPa with an appreciable total elongation of 10.1% is achieved in the novel PHS, which is far superior to commercial 22MnB5 steel (1519 MPa and 10%). The strength increase is predominantly induced by a high density of dislocations and cementite in the novel PHS, while the good ductility is attributed to the refined martensite structure coordinating plastic deformation and the enhanced work-hardening ability and dislocation storage capability mediated by massive cementite. The work can lay foundations for designing high-strength PHSs with good ductility.

Microstructure evolution and strengthening mechanism of air-hardening steel subjected to the austenitizing annealing treatment

The microstructure evolution and mechanical properties of air-hardening steel subjected to different austenitizing annealing treatments were investigated in this study and, especially, the precipitation behavior of the steel was analyzed, as well as the strengthening mechanism of the steel was elucidated on the basis of systematic microstructural characterization. Results reveal that a ferrite + martensite dual-phase structure with about 700 MPa tensile strength and 20% elongation can be obtained by austenitizing the experimental steel in the range of 750∼800 °C; while austenitizing between 850 °C and 950 °C results in granular bainite + lath bainite with about 950 MPa tensile strength and 12% elongation. The experimental steel has the highest strength after austenitizing at 900 °C with lots of nano-scale (Ti, Mo, V)C particles distributed in its matrix. Quantitative calculation results illustrate that the main strengthening factors are grain refinement strengthening, dislocation strengthening and precipitation strengthening. In addition, due to the potential interaction effect between different strengthening factors, a modified strengthening model is proposed to describe the strengthening behavior of the air-hardening steel when it is heat-treated in the two-phase region.

Визначення здатності до дисперсійного твердіння нової штампової сталі з регульованим аустенітним перетворенням

The chemical composition of the stamping steel for high operating temperatures (above 700 °C) with controlled austenitic transformation during operation (CATO) was adjusted to implement its hardening by the dispersion hardening (aging) mechanism. The base steel was chosen as 3Х3Н8М7Ф, in which quenching and subsequent aging did not lead to such hardening. It was taken into account that in order to implement dispersion hardening, CATO steels should have a predominantly austenitic (rather than martensitic) structure in the hardened state, which was not provided for the base steel. As a result of changes in the content of Mn, Ni and C in the base steel, it was determined that the required conditions are met by CATO steel of grade 4Х3Н3Г6М7Ф (95 % austenite after quenching with a predominantly ferrite base in the annealed state). The experiments have established the ability of this steel to harden with ageing. Strength growth was determined by high-temperature tensile tests immediately after aging (without intermediate cooling of samples to room temperature), which is a feature of testing steels with CATO. The highest strength growth (compared to the quenched state) is provided by heat treatment in the following mode: quenching 1150 °C, 2 hours, oil and subsequent aging 725 °C, 2 hours (at a test temperature of 750 °C, s0,2 increases to 674 MPa, sВ to 697 MPa). This hardening is due to the release of dispersed particles of the Laves phase of Fe2Mo and carbide of type VC during aging. In the aged state, the steel retains its austenitic structure at high temperatures, and when cooled below 200 °C, it undergoes a γ → α transformation according to martensitic kinetics and acquires a hardness of 49 HRC. The achieved high-temperature (700...900 °C) strength characteristics of 4Х3Н3Г6М7Ф steel are twice as high as those of the high-temperature die steel 5Х3В3МФС (DI23) and are not inferior to the heat-resistant alloy ХН35ВТЮ (EI787). This makes it possible to effectively use it instead of commercially available heat-resistant martensitic die steels at operating temperatures above 700 °C. Keywords: die steels CATO, alloying, quenching, austenitic structure, dispersion hardening, high-temperature strength.

Cause analysis of surface cracks in flash butt welding joint of high manganese steel frog

Surface cracking is one of the typical failures in butt welding joints of high manganese steel railway frogs. Understanding the formation mechanism of such cracks can effectively prevent similar failures from occurring. Herein, assisted with multiple macro and micro characterization tools, we discussed the causes of surface crack formation for a flash butt welding joint of a high manganese steel frog. The results show that the surface cracks are typical intergranular stress corrosion cracks (IGSCC) distributed near the fusion line between the carbon steel rail and the stainless steel medium in the stainless steel side. Acicular martensite exists near the fusion line between carbon steel rail and stainless steel medium, and the residual stress is large. At the same time, there are continuous network chromium carbide precipitates on the austenitic grain boundary of stainless steel. The above two points should be the main reasons for the initiation of cracks on the weld surface. Reduce the proportion of martensite structure by reasonably optimizing the welding cooling rate. Properly temper martensite to reduce the hardness and internal stress in the transition zone. These measures can prevent the occurrence of intergranular cracks on the weld surface.

Martensite Decomposition and Ultrafine Grain Formation during Small Punch Creep Testing of Additively Manufactured Ti64

The creep behaviour of as-built additive-manufactured Ti-6Al-4V alloy was studied through small punch creep test (SPCT) experiments at 450 and 500 °C. The couple stress/minimum strain rate deduced from these tests made it possible to draw a Norton plot showing good agreement with tensile test creep results. The microstructure characterisation within the SPCT specimen evidenced the effect of local strain on microstructure evolution. After interrupted creep at 450 °C, in most deformed areas, the as-built martensite structure was fully decomposed to the α + β equilibrium phases, giving rise to a submicron equiaxed grain structure.

Predicting the martensitic transition temperatures in ternary shape memory alloys Ni0.5Ti[formula omitted]Hf[formula omitted] from first principles

Martensitic transition temperatures (MTTs) can be tuned by alloying binaries with other elements to create multi-component shape memory alloys (SMAs). However, it is inefficient to use the trial-and-error approach to find compositions with desirable operating temperatures because of the large number of combinations of metals possible to form ternaries, quaternaries, etc. Thus it is crucial to develop the theoretical capability of accurately predicting MTTs as a function of composition, in order to provide experimentalists with necessary and reliable guidance. Previous work has focused on developing and applying first-principles methods to compute phase transitions and MTTs in binary SMAs such as NiTi (nitinol), but certain technical problems associated with the multi-component SMAs remain unsolved. In this work, we employed ab initio molecular dynamics (MD) and thermodynamics integration to study the NiTiHf-based high-temperature ternary SMAs. We overcome the technical challenges to accurately obtain the Gibbs free energy in cubic ternaries where the reference structures are unknown. Specifically, we examined the cubic, monoclinic and orthorhombic structures of Ni0.5Ti0.5−xHfx for x∈[0,0.5], and our results suggest that the cubic-to-monoclinic martensitic transition occurs when x<0.08, for x>0.17 the martensitic transition is between the cubic and orthorhombic phases, whereas in between our calculations cannot distinguish these two martensite structures near the MTT. The computed MTTs vs Hf content x are in good agreement with measured data. Thus our current work paves the way for computational design of multi-component SMAs with desired properties.

Microstructure Evolution at Ni/Fe Interface in Dissimilar Metal Weld between Ferritic Steel and Austenitic Stainless Steel.

The formation and evolution of microstructures at the Ni/Fe interface in dissimilar metal weld (DMW) between ferritic steel and austenitic stainless steel were investigated. Layered martensitic structures were noted at the nickel-based weld metal/12Cr2MoWVTiB steel interface after welding and post-weld heat treatment (PWHT). The formation of the interfacial martensite layer during welding was clarified and its evolution during PWHT was discussed by means of scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), electron probe microanalysis (EPMA), focused ion beam (FIB), transmission electron microscopy (TEM), energy dispersive X-ray (EDX), transmission kikuchi diffraction (TKD), phase diagrams, and theoretical analysis. In as-welded DMW, the Ni/Fe interface structures consisted of the BCC quenched martensite layer and the FCC partially mixed zone (PMZ), which was the result of inhomogeneous solid phase transformation due to the chemical composition gradient. During the PWHT process, the BCC interfacial microstructure further evolved to a double-layered structure of tempered martensite and quenched martensite newly formed by local re-austenitization and austenite-martensite transformation. These types of martensitic structures induced inhomogeneous hardness distribution near the Ni/Fe interface, aggravating the mismatch of interfacial mechanical properties, which was a potential factor contributing to the degradation and failure of DMW.

Effect of intrinsic thermal cycles on the microstructure and mechanical properties of heat affect zones in laser cladding coatings on full-scale rails

Laser cladding (LC) wear-resistant alloy on the surface of pearlite rails has been proven to be able to improve their wear resistance significantly. However, the rapid cooling rate in LC will result in the formation of martensite structures with high hardness but low toughness in heat affected zone (HAZ), making the rails' service safety endangered. In this paper, a novel method was proposed to eliminate the un-tempered martensite in U71Mn rail based on the in-situ gradient tempering (IGT) effect induced by the intrinsic thermal cycles in multilayer LC. The influence mechanisms of interlayer and inter-track thermal cycles on the evolutions of microstructure and mechanical properties of HAZs were studied systematically. The results illustrate that the martensite in HAZs can be gradually tempered within the optimal IGT temperature range, and the tempering processing mechanisms are as follows: firstly, the ε-carbides precipitate from HAZs and then dissolve to form granular cementites. Then, the cementites form colonies of lathlike particles with similar orientations. Finally, a composite structure consisting of fine-tempered sorbite and granular cementites forms, in which the lamellar spacing of sorbite is <1/5 of that of the original pearlite, and the proportion of the high angle grain boundaries has increased by 2.2 times. During the tempering process, the microhardness of HAZs gradually decreases, accompanied by the increase of the bending properties therein. The ultimate bending strength and fracture strain of the specimens with fully tempered HAZs are enhanced to be about 1.6 and 5.5 times as much as those of the specimens with fully quenched HAZs, even much better than the substrate.

Strength-ductility synergy through tailoring heterostructures of hot-rolled ferritic-martensitic steels containing varying Si contents

By utilizing the feature that adding Si is able to effectively increase Ac1 and Ac3 temperatures of ferritic-martensitic (FM) steels, four FM steel sheets with different Si additions (0–1.0 wt%) were prepared by hot rolling at the same intercritical temperature to obtain various heterostructures. Their mechanical properties were evaluated and well correlated with detailed microstructural characteristics revealed by multiple characterization methods. Results show that the 0 Si specimen has a nearly complete martensitic structure; the 0.4 Si specimen consists of ∼23.5 vol% island-like ferrites embedded in martensites exhibiting a typical bi-modal structure (BMS); the 0.7 Si specimen consists of ∼46.8 vol% lamellar ferrites alternating with lamellar martensitic structures corresponding to a typical heterogeneous lamella structure (HLS); the 1.0 Si specimen is mostly comprised of ferrites no longer belonging to typical heterostructures. With increasing Si content, sizes of martensitic laths gradually decrease while the ferritic grains are coarsened. The 0.4 Si and 0.7 Si specimens exhibit high values (∼17 GPa%) of the product of ultimate tensile strength (UTS) and total elongation (TE), demonstrating a good strength-ductility synergy. Comprehensive analyses reveal that the 0.4 Si specimen with BMS exhibits a considerable hetero-deformation induced (HDI) strengthening effect, facilitating the production of the highest UTS (1476.3 MPa), while the 0.7 Si specimen with HLS shows a stronger HDI strain hardening effect leading to a higher TE (12.5%). This study could offer an important reference for designing and processing of FM steels with excellent strength-ductility synergy.

Characterization of dry-sliding wear phenomena in a novel martensitic structure based low-carbon Nb and V alloyed steel

The current study investigated unlubricated dry-sliding wear behaviour of a low-carbon Nb+V stabilized microalloyed steel in various treated states, i.e., as-received, direct-quenched (DQ, martensitic-structure) and tempered (T500) samples. The effects of applied normal load on specific wear-rate, worn-surface and sub-surface characteristics have been discussed, enlightening relevant deformation mechanisms. The specific wear-rate is found to be the lowest (2.91 ×10−5 mm3m−1N−1) for the DQ specimen, primarily due to its better combination of hardness, strength, and toughness. SEM investigation of worn-surfaces confirmed that abrasion (i.e., micro-cutting and ploughing) and oxidative wear mechanisms are the dominant phenomena in all the samples, while the counter-face material remained unchanged. The sub-surface analysis indicates the severely deformed region and bending of martensite is only 1–2 µm and 7 µm for the DQ sample, whereas increases to 3–5 µm and 15 µm, respectively, in the T500 specimen.

Development of martensitic/bainitic rolled homogeneous bulletproof (RHBP) steel sheets for civilian applications

ABSTRACT Bulletproof steel sheets are used for civilian applications like armouring cash money transfer vehicles and bank front points. The present work is dealing with controlled hot-flat rolling and post heat treatment cycle to develop rolled homogeneous bulletproof steel sheets for civilian applications. The steel alloy contains 0.3% C beside 0.93% Cr, 1.76% Ni and 0.62% Mo. The steel is additionally micro-alloyed with 0.004% B. 80 mm thickness steel slabs were controlled forged and followed by hot-flat rolling into 3 mm thickness sheets. A post heat treatment cycle was carried out for creation of bainite beside the martensitic structure to secure ballistic perforation resistance. Strips treated for 10 min. holding in a salt bath at 400 °C followed by water quenching contain 44% bainite and 56% martensite, possessing 388 HB, and present 1647 MPa σu and 1610 MPa σy. In addition to bainite and martensite phases, the microstructure contains ε-carbides measuring 600–800 nm. The ɛ-carbides were found embedded in the bainite aggregates and between the martensite laths. The sheets treated for 5 min. holding in the salt bath followed by water quenching showed up the highest value of σy indicating the highest resistance perforation among the others.

Synergistic effect of well/over-tempered hierarchical martensitic structure and carbides (M23C6 and MX) on austenite growth in 9Cr steel

To clarify the synergistic effect of well/over-tempered hierarchical martensitic structure and carbides (M23C6 and MX) on austenite growth, the austenite growth during step-heat austenitization for a selected 9Cr steel was investigated by dilatometry, multi-scale characterization and cellular automaton simulation. The austenite grain inherits the geometrical characteristics of the hierarchical martensite substructure to a significant extent through covariant and free growth. In particular, the initially heterogeneous grains with non-uniform martensitic substructure can easily produce mixed and heterogeneous grains. Step isothermal heating under AC1 can promote the evolution of martensitic structure to recrystallized ferrite and recovered equiaxed substructure, associated with coarsening of M23C6 and precipitation of MC. Apart from the recrystallized ferrite promoting the growth of equiaxed austenite grains, the recovered approximate equiaxed substructure decorated with coarse M23C6 and a large amount of MX can promote the subsequent development of fine spherical austenite grains by reducing the abnormal austenite growth and increasing the resistance to interfacial migration. The synergistic effect of the well/over tempered martensitic hierarchical structure and the carbides (M23C6, MX) is critical to the final austenite grain distribution. A window of critical temperature values for step heating austenitization to generate homogeneous austenite grain growth was established by exploiting the inheritance of the equiaxed substructure and reasonably reducing abnormal growth.

Mechanical characteristics and stretch-bend failure analysis on ultra high frequency pulsed gas tungsten arc welded thin FSS 409/430 dissimilar joints

The Mechanical and Stretch-Bend Failure studies on Ultra High Frequency Pulsed Gas Tungsten Arc Welded dissimilar joints of AISI409-AISI430 Ferritic Stainless Steels were conducted. Welding was conducted with 5 ultra high frequencies (50 Hz, 150 Hz, 250 Hz, 350 Hz, 450 Hz). Mechanical characteristics evaluation on the joints included tensile strength, microhardness variations across the welds and creep. Microstructural and metallurgical investigations included weld cross section evaluation, comparing grain variations in high, medium and low thermal heat affected zones, weld zones and base material region. Stretch bend failure studies included studies on angular distortion, fracture limit strain, and coefficient of friction. Tests revealed that joints welded at 350 Hz was better, compared to other joints. Dissimilar AISI409-AISI430 joint fabricated at 350 Hz exhibited 267 ± 3 MPa as yield and 409 ± 6 MPa and as ultimate tensile strength. Its creep fracture duration was 72.7 min (highest among the joints). Microstructural studies revealed grain growth, partially coarse and partially fine grains in heat affected zones. Depending on the difference in grain sizes, on both sides of the welds, heat affected regions were identified as three distinct zones. In AISI430 side; high temperature austenitic, martensitic, delta ferrites and in AISI409 side; needle like martensitic structures, mixture of ferritic-austenitic, δ-ferrite with carbide precipitation were found in high, medium and low thermal heat affected zones, respectively. On increasing the ultra high frequency pulses, angular distortion increased, fractures changed from tensile/shear type to mixed type. In shear bend tests, on increasing the ratio of radius: thickness, fracture limit strain on outer surface, across sheet thickness, due to stretching increased.

Fatigue crack propagation of the gradient surface-modified layer of high-strength steel

A gradient modified layer can be produced on the high-strength steel surface by carburizing heat treatment. In this study, microstructure characterization and fatigue crack propagation test were carried out on the gradient surface-modified layer of the 18CrNiMo7-6 high-strength steel. With increasing depth of the surface-modified layer, the yield strength and the kernel average misorientation value decrease, and the equivalent grain size of the slatted martensite structure and the number of the large-angle boundaries increase. The orientation difference angle of the point to point pre- and post-fatigue at the crack of the transition layer and the matrix layer increases from less than 2° to approximately 10° and about 4°, respectively. With the increase of the depth of the surface-modified layer, the degree of deformation inside the martensitic packet decreases, while the extent of macroscopic deformation of the material increases. Deformation occurs inside the martensitic packet at the main crack, and there is essentially no deformation inside the martensite packets away from the main crack. On both sides of the main crack, a large number of extrusions parallel to the martensitic lath appear. The large-angle boundaries of the original austenite grain boundary and martensite boundary hinder the propagation of the fatigue crack.

Microstructure evolution and corrosion behaviors of cold-rolled 304 stainless sheets of steel in 3.5% NaCl solution

Austenitic stainless steel (ASS) is widely used in engineering applications due to its good corrosion resistance and mechanical properties. Several studies have indicated that the deformation-induced transformation of martensite in ASS significantly affects its corrosion resistance. However, corrosion resistance behavior in chloride-rich environments is more complex, and different cold-working methods have distinct impacts on localized corrosion. This study investigated the structural and corrosion resistance changes induced by cold rolling in AISI 304 samples. The used samples were initially subjected to a cold-rolling process with a thickness reduction of up to 50%. The results demonstrate an increase in the deformation-induced martensitic transformation and micro-hardness as the level of cold deformation increases. However, higher levels of deformation lead to the fragmentation of the formed a’‑martensite lath structure into smaller laths, ultimately resulting in a predominantly refined and diffuse dislocation-cell-type structure. Potentiodynamic tests were conducted to analyze conventional electrochemical parameters, revealing a reduction in corrosion resistance with increasing cold deformation. This suggests that the formation, amount, and microstructure of a’‑martensite, under imposed strain conditions, induce changes in the studied electrochemical parameters. Additionally, the more deformed samples exhibited a higher current density during passive layer formation, and exhibited more intense metastable pits, suggesting decreased corrosion resistance with higher degrees of deformation.

Effect of different hydrogen Fugacities on the microstructure of additively manufactured Ti-6Al-4V

In this study we compared the microstructural changes in the presence of hydrogen of Ti-6Al-4V alloy prepared by two different additive manufacturing (AM) methods: electron beam melting (EBM) and selective laser melting (SLM). Cathodic hydrogenation of AM Ti-6Al-4V resulted in significant expansion of β Ti phases due to the solute hydrogen, increasing of micro-strains, and α → titanium hydride/βH transformation. It was shown that SLM Ti-6Al-4V with acicular martensitic structure is more prone to hydrogen-induced phase transformation and hydrogen-assisted damage, compared to EBM. Moreover, it was revealed that different hydrogen charging environments cause different microstructural changes in EBM Ti-6Al-4V. Unlike cathodic hydrogen charging, gaseous hydrogen charging at elevated temperature reduced the process-induced micro-strains and promoted Al redistribution within the EBM Ti-6Al-4V. This resulted in massive precipitation of brittle α2-Ti3Al intermetallic compound, which act as a strong hydrogen trapping site aside from the Ti hydride phase.

Effect of heat treatment on microstructure and mechanical properties of 17-4PH stainless steel manufactured by laser-powder bed fusion

The 17-4 precipitation-hardened (PH) stainless steel was prepared by laser-powder bed fusion (L-PBF), and the effects of different aging temperatures on the microstructures and properties of 17-4PH stainless steel were systematically studied. The results show that the 17-4PH stainless steel prepared by laser powder bed fusion requires a solid solution treatment in order to obtain the lath martensite structure, and then the niobium carbides and ε-Cu phase nanoparticles were precipitated by aging treatment to improve the strength of 17-4PH stainless steel. When the aging heat treatment parameter is 450 °C/5 h, the mechanical properties of the 17-4PH stainless steel are better, and the ultimate tensile strength (UTS) and elongation (El) are 1387 MPa and 7.3%, respectively. Compared with the as-printed 17-4PH stainless steel, the ultimate tensile strength of aging heat treatment exhibits an increase of 25.2%, and then, as the increase of aging temperature, the niobium carbides and ε-Cu precipitation phase become coarser, resulting in a decrease in the strength of 17-4PH stainless steel and an increase in plasticity.

Microstructural Evolution and Mechanical Behavior of TA15 Titanium Alloy Fabricated by Selective Laser Melting: Influence of Solution Treatment and Aging

In this study, TA15 titanium alloys were successfully prepared using selective laser melting (SLM). The results show that the microstructure of each TA15 specimen is composed of a large number of acicular α’ martensite crystals accompanied by a lot of dislocations and twin structures in the martensite due to non-equilibrium heating and cooling via SLM. After solution treatment and aging treatment, the martensite structure is successfully transformed into a typical duplex structure and an equiaxial structure. When there is an increase in the solution temperature, the size of the equiaxed primary α phase and the elongation of the specimen gradually increases, while the thickness of the layered secondary α phase and the tensile strength of the specimen decreases accordingly. After solution treatment at 1000 °C, the specimens show the best comprehensive mechanical properties, i.e., a high-temperature tensile strength of 715 MPa and a corresponding elongation of 24.5%. Subsequently, an appropriate solution–aging treatment is proposed to improve the high-temperature mechanical properties of SLMed TA15 titanium alloys in aerospace.