Mechanical Properties and Microstructural Characterization of Cobalt-Chromium (CoCr) Obtained by Casting and Selective Laser Melting (SLM)

The aim of this study is the consolidation of Cobalt-Chromium (CoCr) alloy powder using the additive manufacturing - selective laser melting (SLM) and the investment casting techniques. The research of this study has been applied to their biomaterial applied to development of prosthesis and dental implants. The gas atomized powder are spherical (mean diameter equal to 42,74 μm) and was analyzed by their physical and chemical properties. The microstructure of the powder and specimens was evaluated using optical microscope (OM) and scanning electron microscope with energy-dispersed X-ray spectroscopy (SEM-EDS). The mechanical properties were evaluated of standard samples using a tensile (yield strength, maximum tensile, rupture tensile and elongation), three point bending (transverse rupture strength) and micro hardness tests. The mechanical results indicate higher values for the SLM than casting specimens. The micrographs revealed a characteristic morphology of laser been used in the SLM technique and the dendrites in the casting technique. The microstructure of samples made by SLM is thinner than the samples obtained in the cast.

Download Full-text

Valuation of Mechanical Properties and Microstructural Characterization of ASTM F75 Co-Cr Alloy Obtained by Selective Laser Melting (SLM) and Casting Techniques

Materials Science Forum ◽

10.4028/www.scientific.net/msf.899.323 ◽

2017 ◽

Vol 899 ◽

pp. 323-328 ◽

Cited By ~ 1

Author(s):

Marcello Vertamatti Mergulhão ◽

Carlos Eduardo Podestá ◽

Maurício David Martins das Neves

Keyword(s):

Mechanical Properties ◽

Selective Laser Melting ◽

Rupture Strength ◽

Microstructural Characterization ◽

Tensile Yield Strength ◽

Uniaxial Tensile ◽

Laser Melting ◽

Standard Samples ◽

X Ray ◽

Astm F75

Advances in processes using the powder metallurgy techniques are making this technology competitive compared to the other traditional manufacturing processes, especially in medicine area. The additive rapid prototyping technique – selective laser melting (SLM) was applied in a biomaterial of CoCrMoFe alloy (ASTM F75), to study the mechanical properties and microstructural characterization in comparison between the conventional technique – casting. The gas atomized powder was investigated by their physical (as apparent density, bulk density and flow rate) and the chemical properties. The powder was analyzed using scanning electron microscope with energy-dispersed X-ray spectroscopy (SEM-EDS) and X-ray fluorescence. Specimens of standard samples were manufactured using these techniques to evaluate the mechanical properties as uniaxial tensile (yield strength, rupture tensile and elongation), transverse rupture strength and the micro hardness. The mechanical properties showed higher values in the SLM specimens than the casting specimens. Before the mechanical tests the specimens were examined using optical microscope (OM) and SEM-EDS. The micrographs revealed a microstructure with finer morphology in the SLM technique and the dendrites in the casting technique.

Download Full-text

Finite Element Analysis of Porous Medical Grade Cobalt Chromium Alloy Structures Produced by Selective Laser Melting

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1133.113 ◽

2016 ◽

Vol 1133 ◽

pp. 113-118

Author(s):

Saiful Anwar Che Ghani ◽

Wan Sharuzi Wan Harun ◽

Zahrul Adnan Mat Taib ◽

Fadzil Faisae Ab Rashid ◽

Ramli Mohd Hazlen ◽

...

Keyword(s):

Mechanical Properties ◽

Finite Element ◽

Selective Laser Melting ◽

Process Analysis ◽

Equivalent Stress ◽

Chromium Alloy ◽

Cobalt Chromium ◽

Laser Melting ◽

Cocr Alloy ◽

Medical Grade

The recent introduction of selective laser melting (SLM) for the processing of medical grade cobalt chromium (CoCr) alloy has led to a complex shape fabrication of porous custom CoCr alloy implants with controlled porosity to meet the requirements of the anatomy and functions at the region of implantation. This paper discusses finite element (FE) analysis and mechanical characterization of porous medical grade CoCr alloy in cubical structures with volume based porosity ranging between 60% and 80% produced using SLM rapid manufacturing process. Analysis by FE is considered beneficial to predict the effective mechanical properties of the porous structures manufactured by SLM due to minimization of the need for expensive and time consuming physical testing. Cellular structures modelling for fabrication with Direct Metal Laser Sintering machine were designed to vary between 60% and 80% to study the effect of structural variation on mechanical properties of the cellular porous structure. ANSYS 14.0 FE modelling software was used to predict the effective elastic modulus of the samples and comparisons were made with the experimental data. FE results show that with the material properties in the functions of porosities, minimum mesh size of 0.2 mm for triangular shape mesh and boundary as well as load conditions as applied in this study, agreement in equivalent stress, strain and deformation with the experimental results can be achieved to some extent. The technique for FE in this study can be used to investigate stress distribution in three dimensional model of real bone.

Download Full-text

High Strength X3NiCoMoTi 18-9-5 Maraging Steel Prepared by Selective Laser Melting from Atomized Powder

Materials ◽

10.3390/ma12244174 ◽

2019 ◽

Vol 12 (24) ◽

pp. 4174 ◽

Cited By ~ 3

Author(s):

Angelina Strakosova ◽

Jiří Kubásek ◽

Alena Michalcová ◽

Filip Průša ◽

Dalibor Vojtěch ◽

...

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

Maraging Steel ◽

Selective Laser Melting ◽

High Strength ◽

Industrial Applications ◽

Tensile Yield Strength ◽

Laser Melting ◽

Maraging Steels ◽

3D Printed

Maraging steels are generally characterized by excellent mechanical properties, which make them ideal for various industrial applications. The application field can be further extended by using selective laser melting (SLM) for additive manufacturing of shape complicated products. However, the final mechanical properties are strongly related to the microstructure conditions. The present work studies the effect of heat treatment on the microstructure and mechanical properties of 3D printed samples prepared from powder of high-strength X3NiCoMoTi 18-9-5 maraging steel. It was found that the as-printed material had quite low mechanical properties. After sufficient heat treatment, the hardness of the material increased from 350 to 620 HV0.1 and the tensile yield strength increased from 1000 MPa up to 2000 MPa. In addition, 3% ductility was maintained. This behavior was primarily affected by strong precipitation during processing.

Download Full-text