Influence of post-heat treatment on microstructure, mechanical, and wear properties of maraging steel fabricated using direct metal laser sintering technique

2021 ◽  
pp. 146442072110373
Author(s):  
Anand Kumar Subramaniyan ◽  
Sudarshan Reddy Anigani ◽  
Snehith Mathias ◽  
Akshay Pathania ◽  
Prasad Raghupatruni ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Maraging Steel ◽  
Laser Sintering ◽  
Direct Metal Laser Sintering ◽  
Wear Properties ◽  
Post Heat Treatment ◽  
Heat Treated Sample ◽  
Heat Treated ◽  
Treated Sample

The post-heat treatment of direct metal laser sintered parts is expected to have superior mechanical properties. Therefore, the purpose of the present study is to investigate the post-heat treatment effect on the microstructure, mechanical and wear properties of direct metal laser sintering processed maraging steel. Hence, a systematic methodology for microstructural characterization, mechanical properties, and tribological performance evaluation was performed. The microstructural examinations were performed using optical and scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction technique. The micro-hardness and tensile properties were determined. The unidirectional sliding wear test was performed using a pin on disc wear testing machine for three different sliding velocities (0.8, 1.2, and 1.6 m/s) and three different normal loads (5, 10, and 15 N). The present study’s findings establish that the post-heat treatment techniques significantly altered the microstructural morphology and features. The results showed that the heat-treated sample had finer and non-continuous microstructure and more complex intermetallic precipitate phases, leading to higher hardness (∼64%) and higher tensile strength properties (70–80%) compared to the as-printed sample. The unidirectional sliding wear test results showed that the sliding velocity significantly affected frictional and wear characteristics of direct metal laser sintering processed maraging steel. The wear resistance of the heat-treated sample was three times higher than the as-printed sample, particularly at higher sliding velocities. In addition, the lower coefficient of friction values (∼24%) was observed for heat-treated sample compared to as-printed sample at higher sliding velocities. The post-heat treatment aids as an effective method to enhance mechanical properties of direct metal laser sintered parts and qualify them for tribological applications. The results endorse the suitability of the heat-treated direct metal laser sintered maraging steel in practical tool and die applications involving extreme tribological operating conditions such as higher sliding velocities and contact stresses.

Microstructure and Properties of Heat-Treated 440C Martensitic Stainless Steel

2013 ◽  
Vol 334-335 ◽  
pp. 105-110 ◽  
Author(s):  
Siti Hawa Mohamed Salleh ◽  
Mohd Nazree Derman ◽  
Mohd Zaidi Omar ◽  
Junaidi Syarif ◽  
S. Abdullah
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Stainless Steel ◽  
Martensitic Stainless Steel ◽  
Ferrite Matrix ◽  
Rapid Quenching ◽  
Heat Treated Sample ◽  
Treatment Processes ◽  
Heat Treated ◽  
Treated Sample

440C martensitic stainless steels are widely used because of their good mechanical properties. The mechanical properties of 440C martensitic stainless steel were evaluated after heat treatment of these materials at various types of heat treatment processes. The initial part of this investigation focused on the microstructures of these 440C steels. Microstructure evaluations from the as-received to the as-tempered condition were described. In the as-received condition, the formations of ferrite matrix and carbide particles were observed in this steel. In contrast, the precipitation of M7C3carbides and martensitic structures were present in this steel due to the rapid quenching process from the high temperature condition. After precipitation heat treatment, the Cr-rich M23C6carbides were identified within the structures. Moreover, a 30 minutes heat-treated sample shows the highest value of hardness compared to the others holding time. Finally, the tempering process had been carried out to complete the whole heat treatment process in addition to construct the secondary hardening phenomenon. It is believed that this phenomenon influenced the value of hardness of the 440C steel.

The Effect of Heat Treatment on the Microstructure and Mechanical Properties of Laser Rapid Forming Ni-Based Alloy Rene88DT

2007 ◽  
Vol 561-565 ◽  
pp. 1051-1054 ◽  
Author(s):  
Fei He ◽  
Jing Chen ◽  
Xiao Ming Zhao ◽  
Xin Lin ◽  
Xiao Jing Xu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Yield Strength ◽  
Quenching Rate ◽  
Heat Treated Sample ◽  
Microstructure And Mechanical Properties ◽  
Heat Treated ◽  
Treated Sample ◽  
Laser Rapid Forming

Laser rapid forming (LRF) is introduced as a novel fabrication process for Ni-based superalloy Rene88DT. The effect of heat treatment parameters of quenching rate and aging time on size and distribution of γ′ precipitation was investigated. The heat treatment parameters were first determined by DSC, and then optimized based on the examination of the microstructure and mechanical properties of heat treated LRF Rene88DT. The experimental results show that, the precipitation of γ′ is inhomogeneously distributed as a result of uneven heat-cycle during LRF in as-deposited Rene88DT, resulting in low mechanical properties. After being heat treated at 1165°C, 2h/AC + 760°C,28h/AC, γ ′ precipitation are homogeneously distributed with the size of 40~60nm, and the tensile strength of heat treated sample shows an increase of 400MPa as compared to that for as-deposited. The yield strength is close to that of the PM+HIP standard.

Comparison of Microstructure and Mechanical Properties of Additively Manufactured and Conventional Maraging Steel

2020 ◽  
Vol 405 ◽  
pp. 133-138
Author(s):  
Ludmila Kučerová ◽  
Andrea Jandová ◽  
Ivana Zetková
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Maraging Steel ◽  
Precipitation Hardening ◽  
High Strength ◽  
Hardness Measurement ◽  
Nickel Steel ◽  
Heat Treated ◽  
Good Material ◽  
Iron Nickel

Maraging steel is an iron-nickel steel alloy, which achieves very good material properties like high toughness, hardness, good weldability, high strength and dimensional stability during heat treatment. In this work, maraging steel 18Ni-300 was manufactured by selective laser melting. It is a method of additive manufacturing (AM) technology, which produces prototypes and functional parts. Sample of additively manufactured and conventional steel with the same chemical composition were tested after in three different states – heat treated (as-built/as-received), solution annealed and precipitation hardened. Resulting microstructures were analysed by light and scanning electron microscopy and mechanical properties were obtained by hardness measurement and tensile test. Cellular martensitic microstructures were observed in additively manufactured samples and conventional maraging steel consisted of lath martensitic microstructures. Very similar mechanical properties were obtained for both steels after the application of the same heat treatment. Ultimate tensile strengths reached 839 – 900 MPa for samples without heat treatment and heat treated by solution annealing, the samples after precipitation hardening had tensile strengths of 1577 – 1711 MPa.

scholarly journals Crystallographic Texture Analysis of As-Built and Heat-Treated Ti6Al4V (ELI) Produced by Direct Metal Laser Sintering

Crystals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 699
Author(s):  
Amos Muiruri ◽  
Maina Maringa ◽  
Willie du Preez
Keyword(s):  
Heat Treatment ◽  
Crystallographic Texture ◽  
Transformation Temperature ◽  
Electron Backscatter Diffraction ◽  
Laser Sintering ◽  
Reconstruction Method ◽  
Direct Metal Laser Sintering ◽  
Β Phase ◽  
Ebsd Data ◽  
Heat Treated

This paper reports on an investigation of crystallographic texture of as-built and heat-treated Ti6Al4V (ELI) produced by direct metal laser sintering (DMLS). The texture analyses were conducted using electron backscatter diffraction (EBSD). The β-phase texture from the obtained EBSD data was ascertained based on a reconstruction method using the Automatic Reconstruction of Parent Grain for EBSD data (ARPGE) program. A significant improvement of the maximum intensity of the texture from the pole figure was also noted upon heat treatment. The as-built samples and samples heat-treated just below the α→β transformation temperature showed a stronger fibrous texture of the reconstructed β-grains with the ⟨100⟩ directions almost parallel to the build direction. The alignment of the fibrous texture in the build direction disappeared after heat treatment above the α→β-grain transformation temperature.

scholarly journals Effects of Post Heat Treatment on the Mechanical Properties of Cold-Rolled Ti/Cu Clad Sheet

Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1672
Author(s):  
Chang-Suk Youn ◽  
Dong-Geun Lee
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Rolling Process ◽  
Post Treatment ◽  
Post Heat Treatment ◽  
Clad Sheet ◽  
Heat Treated ◽  
Bonding Properties ◽  
High Elongation ◽  
Cold Rolled

Titanium and titanium alloys have excellent corrosion and heat resistance, but weak electric and thermal conductivity. The weak conductivity of titanium can be overcome by cladding with copper, which has high conductivity. Although titanium is expensive, it is selected as a material suitable for applications requiring corrosion resistance such as in heat exchangers. This study was to investigate the effect of post heat treatment on the mechanical properties of the Ti/Cu cold-rolled clad plate by using the interfacial diffusion bonding. A titanium clad by cold rolling should be heat-treated after the rolling process to improve the bonding properties through the diffusion of metals and removal of residual stress due to work hardening, despite the easy formation of intermetallic compounds of Ti and Cu. As a result post-treatment, the elongation was improved by more than two times from 21% to max. 53% by the Ti-Cu interface diffusion phenomenon and the average tensile strength of the 450 °C heat-treated specimens was 353 MPa. By securing high elongation while maintaining excellent tensile and yield strength through post-treatment, the formability of Ti-Cu clad plate can be greatly improved.

Thermal Conductivity of Heat Treated and Non-Heat Treated Individual Multiwalled Carbon Nanotubes

2011 ◽  
Author(s):  
Michael F. P. Bifano ◽  
Pankaj B. Kaul ◽  
Vikas Prakash
Keyword(s):  
Thermal Conductivity ◽  
Heat Treatment ◽  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Multiwalled Carbon ◽  
Heat Treated Sample ◽  
Heat Treated ◽  
Treated Sample ◽  
Annealing Heat Treatment

Thermal conductivity measurements of commercially available CVD grown individual multiwalled carbon nanotubes (MWCNTs) are reported. The measurements are performed using the three-omega-based Wollaston T-Type probe method inside a scanning electron microscope (SEM). An average 385% increase in thermal conductivity is measured for those MWCNTs samples which undergo a 20 hour 3000°C post annealing heat treatment. However, in most samples qualitatively characterized defects are found to negate any advantage of the heat treatment process. The highest thermal conductivity measured is 893.0 W/mK and is of a heat-treated sample. These results will help to improve the quality of MWCNT production and aid in the development of highly efficient CNT-structured thermal management devices and engineering materials.

scholarly journals White-Ceramic Conversion on Ti-29Nb-13Ta-4.6Zr Surface for Dental Applications

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Akiko Obata ◽  
Eri Miura-Fujiwara ◽  
Akimitsu Shimizu ◽  
Hirotaka Maeda ◽  
Masaaki Nakai ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Pure Titanium ◽  
Average Roughness ◽  
Heat Treated Sample ◽  
Cell Compatibility ◽  
Heat Treated ◽  
Treated Sample ◽  
Mouse Osteoblast ◽  
Cp Ti

Ti-29Nb-13Ta-4.6Zr (TNTZ) alloy has excellent mechanical properties and bone conductivity. For dental application, TNTZ surfaces were converted to white oxidized layer by a simple heat treatment in air to achieve the formation of aesthetic surfaces. The oxidized layer formed by the heat treatment at 1000°C for 0.5 or 1 hr was whiter and joined to TNTZ substrate more strongly than that formed by the treatment at 900°C. The layer consisted of TiO2(rutile), TiNb2O7, and TiTa2O7and possessed ~30 μm in thickness for the sample heat-treated at 1000°C and ~10 μm for that heat-treated at 900°C. The surface average roughness and the wettability increased after the heat treatment. The spreading and proliferation level of mouse osteoblast-like cell (MC3T3-E1 cell) on the heat-treated sample were almost the same as those on as-prepared one. The cell spreading on TNTZ was better than those on pure titanium (CP Ti) regardless of the heat treatment for the samples. There was no deterioration in thein vitrocell compatibility of TNTZ after the oxidized layer coating by the heat treatment.

Influence of Heat Treatment on Martensitic Transformations in Copper-Based Alloys with Shape Memory Effect

2016 ◽  
Vol 869 ◽  
pp. 474-478
Author(s):  
Luiz Carlos Sekitani da Silva ◽  
Cezar Henrique Gonzalez ◽  
Carlos Augusto do Nascimento Oliveira ◽  
Karla Carolina Alves da Silva
Keyword(s):  
Heat Treatment ◽  
Shape Memory ◽  
Thermal Hysteresis ◽  
Martensitic Transformations ◽  
Scanning Calorimetry ◽  
Critical Temperatures ◽  
Heat Treated Sample ◽  
Heat Treated ◽  
Treated Sample ◽  
Shape Memory Effects

In the present work the copper base alloys with shape memory effects were characterized. The alloys were subjected to three different heat treatments that promoted changes in characteristics of thermoelastic martensitic transformation (transformation temperatures, thermal hysteresis and enthalpies of transformation). The alloys have their microstructures characterized by optical and scanning electron microscopy. Microhardness tests were performed. Differential scanning calorimetry (DSC) was used to evaluate the transformation critical temperatures of alloy and the transformation enthalpies for each heat treated sample. Thermoelastic properties have changed for each heat treatment. In the micrographs of the heat-treated samples was possible to observe the microstructure of the martensitic phase characteristic. They show the presence of martensite platelets (needles) self-accommodation.

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