Effect of internal pores on tensile properties of Co-Cr-Mo alloy fabricated by selective laser melting

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hyeon-Tae Im ◽  
Hyun-Su Kang ◽  
Hyeon-Goo Kang ◽  
Hyo Kyu Kim ◽  
Jun Choi ◽  
...  
Keyword(s):  
Tensile Properties ◽  
Selective Laser Melting ◽  
Volume Fraction ◽  
Tensile Deformation ◽  
Hot Isostatic Pressing ◽  
Tensile Tests ◽  
Laser Melting ◽  
Content Type ◽  
Tensile Deformation Behavior ◽  
Ε Phase

Purpose The purpose of this paper is to examine the effect of internal pores on the tensile properties of a Co–Cr–Mo alloy fabricated by selective laser melting (SLM). Design/methodology/approach The size and volume fraction of pores were controlled through high temperature annealing (HTA) and hot isostatic pressing (HIP). Findings After HTA, the size and fraction of pores decreased compared with the as-built SLM sample, and no pores were observed after HIP. Tensile tests of the HTA and HIP samples showed nearly similar tensile deformation behavior. From the results, the authors found that the size of the internal pores formed in the SLM process had little effect on the tensile properties. The as-built SLM sample had less elongation than the HTA and HIP samples, which would not the effect of porosity, but rather the effect of the residual stress and the retained ε phase after the SLM process. Originality/value Although pores are a main factor that influence the mechanical properties, the effect of pores on the tensile properties of Co–Cr–Mo alloys fabricated by SLM has not been studied. Therefore, in this study, the effect of pores on the tensile properties of a Co–Cr–Mo alloy fabricated by SLM was studied.

scholarly journals Microstructure and mechanical properties relationship of additively manufactured 316L stainless steel by selective laser melting

2019 ◽  
Vol 5 ◽  
pp. 23 ◽  
Author(s):  
Anne-Helene Puichaud ◽  
Camille Flament ◽  
Aziz Chniouel ◽  
Fernando Lomello ◽  
Elodie Rouesne ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Selective Laser Melting ◽  
316L Stainless Steel ◽  
Hot Isostatic Pressing ◽  
Tensile Tests ◽  
Industrial Applications ◽  
Added Value ◽  
Laser Melting ◽  
Microstructure And Mechanical Properties

Additive manufacturing (AM) is rapidly expanding in many industrial applications because of the versatile possibilities of fast and complex fabrication of added value products. This manufacturing process would significantly reduce manufacturing time and development cost for nuclear components. However, the process leads to materials with complex microstructures, and their structural stability for nuclear application is still uncertain. This study focuses on 316L stainless steel fabricated by selective laser melting (SLM) in the context of nuclear application, and compares with a cold-rolled solution annealed 316L sample. The effect of heat treatment (HT) and hot isostatic pressing (HIP) on the microstructure and mechanical properties is discussed. It was found that after HT, the material microstructure remains mostly unchanged, while the HIP treatment removes the materials porosity, and partially re-crystallises the microstructure. Finally, the tensile tests showed excellent results, satisfying RCC-MR code requirements for all AM materials.

The influence of a process interruption on tensile properties of AlSi10Mg samples produced by selective laser melting

2019 ◽  
Vol 25 (8) ◽  
pp. 1442-1452 ◽  
Author(s):  
Vincent Hammond ◽  
Michael Schuch ◽  
Matthias Bleckmann
Keyword(s):  
Tensile Properties ◽  
Selective Laser Melting ◽  
Continuous Process ◽  
Processing Parameters ◽  
Laser Melting ◽  
Content Type ◽  
Random Failure ◽  
Pressure Die Casting ◽  
Suitable Technique ◽  
Cylindrical Samples

Purpose The purpose of this paper is to investigate the influence of a process interruption on the tensile properties of AlSi10Mg samples produced by selective laser melting (SLM). Design/methodology/approach Using identical processing parameters, cylindrical samples were produced in either a continuous or interrupted SLM build operation. The tensile properties and microstructure of the samples were determined as a function of process type as well as orientation. Findings All samples produced in this paper displayed superior tensile properties to those produced in high pressure die casting. In general, the samples produced in the continuous build process had higher strengths and microhardness than those produced in the interrupted process. However, while most samples displayed random failure locations, the vertical samples produced in the interrupted build process showed a strong tendency for localized failure in the vicinity of the stoppage plane. Originality/value This paper demonstrated that samples produced in an interrupted build process tend to have poorer mechanical properties than those produced in a continuous process. Together, these observations highlight the importance of a suitable technique for restarting and completing an interrupted build process to ensure the production of high quality components.

scholarly journals Net-shape manufacturing using hybrid selective laser melting/hot isostatic pressing

2017 ◽  
Vol 23 (4) ◽  
pp. 720-726 ◽  
Author(s):  
Hany Hassanin ◽  
Khamis Essa ◽  
Chunlei Qiu ◽  
Ali M. Abdelhafeez ◽  
Nicholas J.E. Adkins ◽  
...  
Keyword(s):  
Selective Laser Melting ◽  
Hot Isostatic Pressing ◽  
Grain Structure ◽  
Full Density ◽  
Fe Model ◽  
Laser Melting ◽  
Fe Modelling ◽  
Content Type ◽  
Isostatic Pressing ◽  
Hip Process

Purpose The purpose of this study is to develop a manufacturing technology using hybrid selective laser melting/hot isostatic pressing (SLM/HIP) process to produce full density net-shape components more rapidly and at lower cost than processing by SLM alone. Design/methodology/approach Ti-6Al-4V powder was encapsulated in situ by the production of as-SLMed shell prior to the HIP process. After HIPping, the SLM shell is an integral part of the final component. Finite element (FE) modelling based on pure plasticity theory of porous metal coupled with an iterative procedure has been adopted to simulate HIPping of the encapsulated Ti-6Al-4V powder and SLMed shell. Two demonstrator parts have been modelled, designed, produced and experimentally validated. Geometrical analysis and microstructural characterisation have been carried out to demonstrate the efficiency of the process. Findings The FE model is in agreement with the measured data obtained and confirms that the design of the shell affects the resulting deformed parts. In addition, the scanning electron microscope (SEM) and Electron backscatter diffraction EBSD (EBSD) of the interior and exterior parts reveal a considerably different grain structure and crystallographic orientation with a good bonding between the SLMed shell and HIPped powder. Originality/value An approach to improve SLM productivity by combining it with HIP is developed to further innovate the advanced manufacturing field. The possibility of the hybrid SLS/HIP supported by FEA simulation as a net shape manufacturing process for fabrication of high performance parts has been demonstrated.

scholarly journals Structure, Texture and Tensile Properties of Ti6Al4V Produced by Selective Laser Melting

2019 ◽  
Vol 25 (25) ◽  
pp. 60-65
Author(s):  
Radomila Konečná ◽  
Denisa Medvecká ◽  
Gianni Nicoletto
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Additive Manufacturing ◽  
Tensile Properties ◽  
Selective Laser Melting ◽  
Hot Isostatic Pressing ◽  
Ti6al4v Alloy ◽  
Laser Melting ◽  
Isostatic Pressing ◽  
Material Defects

Abstract Additive manufacturing has recently expanded its potential with the development of selective laser melting (SLM) of metallic powders. This study investigates the relation between the mechanical properties and the microstructure of Ti6Al4V alloy produced by SLM followed by a hot isostatic pressing (HIP) treatment. HIP treatment minimizes the detrimental influence of material defects. Tensile specimens produced with reference to specific building axes were prepared using a Renishaw A250 system. It has been found that the tensile strength and elongation depend on specimen building direction. Microstructural and textural characterizations were carried out to identify the source of differences.

Customized implants with specific properties, made by selective laser melting

2015 ◽  
Vol 21 (1) ◽  
pp. 98-104 ◽  
Author(s):  
Dan Leordean ◽  
Cristian Dudescu ◽  
Teodora Marcu ◽  
Petru Berce ◽  
Nicolae Balc
Keyword(s):  
Selective Laser Melting ◽  
Laser Power ◽  
Design Procedure ◽  
Tensile Tests ◽  
Laser Melting ◽  
Content Type ◽  
Detailed Case ◽  
Design And Manufacture ◽  
Practical Implications

Purpose – The purpose of this paper was to present how customized implants could be made with specific properties, by setting different values of the laser power, within the selective laser melting (SLM) process. A detailed case study was undertaken and a new multi-structured femoral prosthesis was designed and analyzed, to simulate its behavior for a specific case study. Design/methodology/approach – The materials and manufacturing methods are presented, with details regarding the SLM process, using the Realizer 250 machine. The laser power was varied between 50 and 200 W, thus obtaining samples with different physical and mechanical characteristics. All those sample parts were characterized and their properties were measured. Findings – A practical methodology was found to produce multi-structured implants by SLM. Significant changes of the porosity and properties were found, when modifying the laser power at the SLM machine. The studies have indicated an open porosity varying between 24.810.83 per cent. Tensile tests of the samples showed Young’s modulus values varying between 13.5 and 104.5 GPa and an ultimate stress between 20.2 and 497.5 MPa. Research limitations/implications – There is no Additive Manufacturing (AM) machine available, to work with different laser power values, in different regions of the same section of the implant. Hence, a multi-structured implant cannot be obtained directly. Practical implications – The prosthesis should be specifically designed to contain separate models/regions to be made with appropriate laser power values. Originality/value – This paper presents a new method to design and manufacture a multi-structured implant, using the existing AM equipment. A detailed case study is presented, showing the design procedure, the way to simulate its behavior and the methods to produce the implants by SLM.

Mechanical Properties of Selective Laser-Melted Components of Alsi10mg for Prototype Vehicles

2021 ◽  
Vol 1016 ◽  
pp. 399-406
Author(s):  
Christoph Egger ◽  
Florian Grünbart ◽  
Zahra Silvayeh ◽  
Olga Šulcová ◽  
Christoph Seper ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Selective Laser Melting ◽  
Computer Aided Design ◽  
Cast Alloy ◽  
Hot Isostatic Pressing ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Laser Melting ◽  
Pressure Die Casting

Fabrication of aluminum alloy components by traditional high-pressure die casting (HPDC) requires cost- and time-consuming tooling of steel dies, which makes HPDC uneconomic for producing low-volume components or prototypes. In comparison, powder bed-based additive manufacturing, e.g. selective laser melting (SLM), enables rapid prototyping and production of even complex-shaped components directly from computer-aided design models without needing expensive tools. However, SLM prototype components must have almost identical mechanical properties to HPDC serial components in order to emulate their functionality under different load conditions. In this work uniaxial tensile properties of cast alloy AlSi10MnMg (EN AC-43500) in condition T7, i.e. with 120-170 MPa yield stress, 200-240 MPa tensile strength and 9-12 % strain at fracture, shall be attained using selective laser melting of powder alloy AlSi10Mg (EN AC-43000). These properties were achieved by tailored heat treatment. Furthermore, the effect of hot isostatic pressing (HIP) was investigated. The results of the tensile tests confirmed the basic feasibility of substituting HPDC components with SLM components for prototyping. In particular, similar tensile strength and uniform strain were achieved for SLM samples in condition O, i.e. for SLM samples which were only annealed.

Melting, fusion and solidification behaviors of Ti-6Al-4V alloy in selective laser melting at different scanning speeds

2020 ◽  
Vol 26 (7) ◽  
pp. 1209-1215 ◽  
Author(s):  
Snehashis Pal ◽  
Gorazd Lojen ◽  
Nenad Gubeljak ◽  
Vanja Kokol ◽  
Igor Drstvensek
Keyword(s):  
Tensile Properties ◽  
Selective Laser Melting ◽  
Solidification Process ◽  
Fabrication Process ◽  
Laser Melting ◽  
Content Type ◽  
Melt Pool ◽  
High Thermal Gradient ◽  
Thermal Phenomena ◽  
Pool Formation

Purpose Melting, fusion and solidification are the principal mechanisms used in selective laser melting to produce a product. Several thermal phenomena occur during the fabrication process, such as powder melting, melt pool formation, mixing of materials (fusion), rapid solidification, re-melting, high thermal gradient, reheating and cooling. These phenomena result in several types of pores, defects, irregular surfaces, bending and residual stress. This paper aims to focus on the physical behaviors of Ti-6Al-4V alloy at several scanning speeds and their effect on porosity and metallurgical properties. Design/methodology/approach Seven scanning speeds between 150  and 1000 mm/s were chosen to observe the occurrence of different pores, defects and microstructural formations and their effect on hardness and tensile properties. Findings The various mentioned malformations occur due to the results of possible uncertainties during the melting-fusion-solidification process. Size, shape, number, location and content of the pores varied in different samples. The a cicular a' size changes with different scanning speeds. Eventually, both porosity and microstructure have shown influential consequences on the hardness and tensile properties in the samples manufactured with different scanning speeds. Originality/value This study showed the adverse effects of different physical behaviors that occurred during the fabrication process, leading to the formation of complex pores. The causations and plausible solutions of the pore formation are interpreted in this paper. The authors observe that a circular a' size differed with scanning speeds, and these influence the mechanical properties.

scholarly journals Effect of Shielding Gas Volume Flow on the Consistency of Microstructure and Tensile Properties of 316L Manufactured by Selective Laser Melting

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 205
Author(s):  
Ruochen Ding ◽  
Jun Yao ◽  
Baorui Du ◽  
Kailun Li ◽  
Tao Li ◽  
...  
Keyword(s):  
Tensile Properties ◽  
Selective Laser Melting ◽  
Mass Production ◽  
Strong Influence ◽  
Base Plate ◽  
Volume Flow ◽  
Shielding Gas ◽  
Laser Melting ◽  
Gas Volume ◽  
By Products

In recent years, selective laser melting (SLM) has been widely used in aerospace, automobile, biomedicine and other fields. However, there still remain many challenges to obtain consistent parts at the different positions on the base plate, which could be harmful to the industrial mass-production. In SLM process, the process by-products that flow with the shielding gas may influence the microstructure and tensile properties of the parts placed on different positions of the base plate. In this study, the velocity field of the shielding gas with different shielding gas volume flows was simulated. The tensile properties of the samples fabricated with different shielding gas volume flow were experimentally studied. The results show that the shielding gas volume flow has a strong influence on the sample consistency, and proper increase in shielding gas volume flows can be beneficial to consistency and tensile strength.

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