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Effect of Heat Treatment on Microstructure and Properties of FGH4096M Superalloy Processed by Selective Laser Melting
摘要： A self-designed nickel-based superalloy, designated as FGH4096M, was prepared by selective laser melting (SLM). Different heat treatments were performed to improve the mechanical properties of the SLM alloy through optimizing the microstructures and the features of γ′ precipitates. Compared with the as-deposited alloy, the columnar grains with dendritic structures and equiaxed structures were retained in the alloy after direct aging, but a large amount of tertiary γ′ phase precipitated, especially around the sub-grain boundaries, resulting in the highest tensile strength but the lowest elongation. During solid solution and aging treatment (SSA), the recovery and recrystallization occurring in the alloy facilitated the grains to be equiaxed with the increase of solution temperature. For lower solution temperature (below 1100 ℃), the secondary γ′ precipitates decreased with the increase of solution temperature, while the tertiary γ′ precipitates from the subsequent aging process gradually increased; for higher solution temperature over 1100 ℃, exceeding the complete dissolution temperature of the γ′ phase, only tertiary γ′ precipitates from the subsequent aging process were uniformly distributed in the alloy. After double solid solution (1170 ℃ + 1050 ℃) + aging heat treatment (DSSA), there were three sizes of γ′ precipitates in the alloy. In general, the SLM + SSA (1130 ℃) alloy obtained the best comprehensive properties, which could be related to the homogenized microstructures and the uniform and dense distribution of single sized tertiary γ′ precipitates in the alloy.
关键词： Microstructure,Nickel-based superalloy,Selective laser melting,Tensile,γ′ phase,Heat treatment
更新于2025-09-12 10:27:22
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Study of heat treatment impact on the surface defects appearance on samples obtained by selective laser melting of Ti-6Al-4V during chemical polishing
摘要： Among advantages of selective laser melting (SLM) there are some problems in titanium alloys surface roughness after the sintering. Present work illustrates results of roughness measurements of Ti-6Al-44V titanium alloy samples after selective laser melting, heat treatment, mechanical brushing and acid polishing. It was found that surface roughness of SLM samples depends on heat treatment and chemical polishing modes; the biggest roughness is noted after the oil quenching from 950 (cid:1)C with subsequent aging at 650 (cid:1)C during 120 min. The best surface quality was obtained after annealing for 2 h at 650 (cid:1)C, water quenching at 950 (cid:1)C, mechanical brushing and chemical polishing.
关键词： Chemical polishing,Titanium alloy,Heat treatment,Selective laser melting,Surface roughness
更新于2025-09-12 10:27:22
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Laser beam welding of DP980 dual phase steel at high temperatures
摘要： Dual phase steels have been used in safety components for the automotive industry and represents a standard in terms of energy absorbing steel alloys. After welding, these components present a martensitic transformation in the fusion and heat-a?ected zones with an intrinsic brittleness. The current contribution presents a procedure where the DP980 steel sheet is kept at a given temperature during and after the laser weld in order to generate bainite instead of martensite. The results using an isothermal treatment at 527 °C shown a microstructure composed by grain boundary and bainitic ferrite and retained austenite with a constant hardness in the base material and heat-a?ected and fusion zones of 280 HV. The room temperature welds present hardness values between 320 and 500 HV. The high-temperature welds also shown a decrease in the maximum residual stress at the weld centerline by 1/3, with a consequential reduction in the warp of the joined component.
关键词： Heat treatment,Hardness testing,Laser beam welding,Dual phase steels
更新于2025-09-11 14:15:04
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The Effects of Heat Treatment on Microstructure and Mechanical Properties of Tribaloy 400 Coatings Deposited by Laser Cladding
摘要： The effects of heat treatment on the microstructure, microhardness, nanohardness and wear resistance of Tribaloy 400 coatings prepared by laser cladding on 304 stainless steel were studied in this paper. The results show that the microstructures of Tribaloy 400 laser cladding layer are cobalt matrix dendrites and eutectic structure. After the heat treatment at 1250 °C for 1 h, the eutectic structure disappears and the strip-like Laves phase is formed on the Co matrix. Meanwhile, the hardness is obviously improved. After the heat treatment at 1250 °C for 1 h and then 900 °C for 4 h, a small amount of e-Co appears, the strip-like Laves phases become coarser and blunter, and some of the strip structures combine together to form blocky structures, and the hardness is decreased. The wear resistance of the samples at 600 °C is better than that at RT since the hardness of the Laves phase increases with the rise in temperature.
关键词： Laves phase,wear resistance,hardness,heat treatment,Tribaloy alloy
更新于2025-09-10 09:29:36
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Heat-Treatment Induced Magnetic Anisotropy of GaMnSb Films
摘要： Conditions and mechanisms of controlled variation of the magnetic anisotropy of GaMnSb films containing magnetic MnSb nanoinclusions by means of heat treatment have been determined. For this purpose, the temperature and magnetic-field dependences of the magnetic moments of samples before and after thermal annealing were measured using a SQUID magnetometer. It is established that the heat treatment of GaMnSb films leads to a significant increase in the values of characteristics determined by the magnetic anisotropy, including the growth of blocking temperature (from 95 to 390 K) and the magnetic anisotropy field (from 330 to 630 Oe). Results of transmission electron microscopy investigation indicate that a change in the magnetic anisotropy of GaMnSb films as a result of their thermal annealing can be related to a transition of the crystalline structure of magnetic MnSb nanoinclusions from hexagonal (space group P62/mmc) to cubic (space group F-43m).
关键词： magnetic anisotropy,GaMnSb films,SQUID magnetometer,transmission electron microscopy,MnSb nanoinclusions,heat treatment
更新于2025-09-10 09:29:36
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AIP Conference Proceedings [Author(s) 3RD INTERNATIONAL CONFERENCE ON MATERIALS SCIENCE, RESOURCE AND ENVIRONMENTAL ENGINEERING (MSREE 2018) - Changsha City, China (26–28 October 2018)] - Vacuum heat treated multilayer graphene
摘要： The influence of different temperature vacuum heat treatment on the structure of multilayer graphene was studied. The research results can be served as the early attempt for vacuum sintered graphene reinforced metal matrix composites. XRD, Raman and HRTEM results showed the structure defects of vacuum heat treated multilayer graphene was increased as the increasing of heat treatment temperature, but there was no fundamental change on the microstructure and properties of heat treated graphene. Therefore, it is possible to make graphene reinforced metal matrix composites by vacuum sintering.
关键词： Vacuum Heat Treatment,Graphene,Structure Defects
更新于2025-09-04 15:30:14