Investigation of the effects of different heat treatment parameters on the corrosion and mechanical properties of the AlSi10Mg alloy produced with direct metal laser sintering

2019 ◽  
Vol 71 (3) ◽  
pp. 365-373
Author(s):  
Gökhan Özer ◽  
Gürkan Tarakçi ◽  
Mustafa S. Yilmaz ◽  
Zafer Ç. Öter ◽  
Ömer Sürmen ◽  
...  
Author(s):  
Anand Kumar Subramaniyan ◽  
Sudarshan Reddy Anigani ◽  
Snehith Mathias ◽  
Akshay Pathania ◽  
Prasad Raghupatruni ◽  
...  

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.


2019 ◽  
Vol 290 ◽  
pp. 08010
Author(s):  
Karolina Karolewska ◽  
Bogdan Ligaj

The most commonly used technology among the additive manufacturing is Direct Metal Laser Sintering (DMLS). This process is based on selective laser sintering (SLS). The method gained its popularity due to the possibility of producing metal parts of any geometry, which would be difficult or impossible to obtain by the use of conventional manufacturing techniques. Materials used in the elements manufacturing process are: titanium alloys (e.g. Ti6Al4V), aluminium alloy AlSi10Mg, etc. Elements printed from Ti6Al4V titanium alloy find their application in many industries. Details produced by additive technology are often used in medicine as skeletal, and dental implants. Another example of the DMLS elements use is the aerospace industry. In this area, the additive manufacturing technology produces, i.a. parts of turbines. In addition to the aerospace and medical industries, DMLS technology is also used in motorsport for exhaust pipes or the gearbox parts. The research objects are samples for static tests. These samples were made of Ti6Al4V alloy by the DMLS method and the rolling method from a drawn rod. The aim of the paper is the mechanical properties comparative analysis of the Ti6Al4V alloy produced by the DMLS method under static loading conditions and microstructure analysis of this material.


Crystals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 699
Author(s):  
Amos Muiruri ◽  
Maina Maringa ◽  
Willie du Preez

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.


2014 ◽  
Vol 903 ◽  
pp. 114-117 ◽  
Author(s):  
Izhar Abd Aziz ◽  
Brian Gabbitas ◽  
Mark Stanford

The purpose of this work is to investigate the microstructure and tensile strength of Ti6Al4V pre-alloyed powders produced by a direct metal laser sintering technique. Traditionally, Ti6Al4V products for biomedical applications were produced through hot working or machining of wrought semi-finished products. A change in the production route for manufacturing Ti6Al4V products, from the more traditional methods to an additive manufacturing route, requires an investigation of microstructure and mechanical properties because these are strongly influenced by the production route. The microstructure obtained through rapid solidification during laser sintering shows a very fine α+β lamellar morphology. There is also evidence of martensite which was expected due to high solidification rate of the liquid pool from a temperature above the β-transus during the laser sintering process. Structurally, good mechanical properties which are comparable to the bulk material were obtained.


2018 ◽  
Vol 24 (2) ◽  
pp. 276-284 ◽  
Author(s):  
Hamza Hassn Alsalla ◽  
Christopher Smith ◽  
Liang Hao

Purpose The purpose of this paper is to study new process parameters which were selected to achieve the full density of Ti-6Al-4V samples in different building orientations and investigate fracture toughness property and its relation to the microstructure, an area which has not previously been reported in full detail and which may offer information to a designer. Direct metal laser sintering (DMLS) is an additive manufacturing technique that directly manufactures three-dimensional parts, layer-by-layer, to scan and melt metal powders for aerospace applications. Design/methodology/approach Hardness and tensile tests were carried out to evaluate the effect of consolidation on the mechanical performance of specimens made at three different building directions. Optical and electron microscopy were used to characterise the microstructure of the DMLS specimens and their effects on the fractures and mechanical properties. Findings It was found that the built samples have an excellent density at 4.5 g/cm, and the sample surfaces parallel to the building direction are rougher than the perpendicular surfaces. The fracture toughness result was higher than that of the cast material for the same alloy and higher than the Ti-6Al-4V parts fabricated by electron beam melting. This results in the superior mechanical properties of DMLS, while slightly lower in the zy direction owing to cracks, porosity and surface finish. Research limitations/implications The tensile strength was found to be higher than the wrought material, and the samples exhibited brittle fractures owing to the martensitic phase, which is caused by a high temperature gradient, and the mechanical properties change with the change in the microstructures at different building directions. Originality/value This paper contains original research.


2021 ◽  
Vol 93 (3) ◽  
pp. 49-56
Author(s):  
Jakub Ciftci ◽  
Ryszard Sitek ◽  
Jarosław Mizera

The group of nickel based superalloys produced in the DMLS (Direct Metal Laser Sintering) process is limited to materials, which produced conventionally do not have properties to allow to use them for rotating components of aircraft engines. This work attempts to optimize the technological parameters of the DMLS process for the Inconel 713C nickel superalloy. A heat treatment was performed for selected samples to investigate the effect on the morphology of the Ni3Al phase. The microstructure analysis and hardness tests were carried out. The material after the DMLS process was characterized by the presence of much smaller dendrites than the cast material and exceeded its hardness. For the tested variants of heat treatment, the material was characterized by smaller sizes of the Ni3Al phase. In order to ensure the stability of the microstructure, an optimization of the dedicated heat treatment after the DMLS process is required, as the standard heat treatment for Inconel 713C cast nickel superalloy does not fully recrystallize the material.


Author(s):  
Genrik Mordas ◽  
Ada Steponavičiūtė ◽  
Aušra Selskienė ◽  
Jurijus Tretjakovas ◽  
Sergejus Borodinas

Additive manufacturing (AM) is a type of manufacturing technologies whereby the material is added a layer upon layer to produce a 3D object. Produced 3D parts are applied in such industry sectors as space, aviation, automotive, building and has excellent future promises. Ourdays, the commercialy promised technique for metal manufacturing is Direct Metal Laser Sintering (DMLS). Our study concentrated on the investigation of the mechanical properties of produced17-4H (stainless steel) parts using DMLS. The effect of the DMLS process parameters (laser power, scanning speed and energy density) on the ultimate strength, yield strength and Young’s modulus was determined. We showed an evolution of the microstructure. The detected defects were classified. This study allowed to determine the optimal regimes of DMLS for SS 17-4H and describe mechanical properties of the produced parts as well as helped to show future possibilities of DMLS development.


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