scholarly journals Effects of manufacturing parameters, heat treatment, and machining on the physical and mechanical properties of 13Cr10Ni1.7Mo2Al0.4Mn0.4Si steel processed by laser powder bed fusion

2021 ◽  
pp. 142402
Author(s):  
Shahriar Afkhami ◽  
Vahid Javaheri ◽  
Edris Dabiri ◽  
Heidi Piili ◽  
Timo Björk
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Physical And Mechanical Properties ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Powder Bed ◽  
Manufacturing Parameters

scholarly journals Effect of Particle Size Distribution on Laser Powder Bed Fusion Manufacturability of Copper

2021 ◽  
Author(s):  
Massimiliano Bonesso ◽  
Pietro Rebesan ◽  
Claudio Gennari ◽  
Simone Mancin ◽  
Razvan Dima ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Physical And Mechanical Properties ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Powder Bed ◽  
Cooling Channels ◽  
Scan Speed

AbstractOne of the major benefits of the Laser Powder Bed Fusion (LPBF) technology is the possibility of fabrication of complex geometries and features in only one-step of production. In the case of heat exchangers in particular, this is very convenient for the fabrication of conformal cooling channels which can improve the performance of the heat transfer capability. Yet, obtaining dense copper parts printed via LPBF presents two major problems: the high reflectivity of 1 μm (the wavelength of commonly used laser sources) and the high thermal conductivity of copper that limits the maximum local temperature that can be attained. This leads to the formation of porous parts.In this contribution, the influence of the particle size distribution of the powder on the physical and mechanical properties of parts produced via LPBF is studied. Three copper powders lots with different particle size distributions are used in this study. The effect on densification from two laser scan parameters (scan speed and hatching distance) and the influence of contours scans on the lateral surface roughness is reported. Subsequently, samples manufactured with the optimal process parameters are tested for thermal and mechanical properties evaluation.

scholarly journals In Situ Formation of a Metastable β-Ti Alloy by Laser Powder Bed Fusion (L-PBF) of Vanadium and Iron Modified Ti-6Al-4V

Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1067 ◽  
Author(s):  
Florian Huber ◽  
Thomas Papke ◽  
Christian Scheitler ◽  
Lukas Hanrieder ◽  
Marion Merklein ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Homogeneous Element ◽  
Alloy Formation ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Powder Bed ◽  
Β Phase ◽  
Stabilizing Effect

The aim of this work is to investigate the β-Ti-phase-stabilizing effect of vanadium and iron added to Ti-6Al-4V powder by means of heterogeneous powder mixtures and in situ alloy-formation during laser powder bed fusion (L-PBF). The resulting microstructure was analyzed by metallographic methods, scanning electron microscopy (SEM), and electron backscatter diffraction (EBSD). The mechanical properties were characterized by compression tests, both prior to and after heat-treating. Energy dispersive X-ray spectroscopy showed a homogeneous element distribution, proving the feasibility of in situ alloying by LPBF. Due to the β-phase-stabilizing effect of V and Fe added to Ti-6Al-4V, instead of an α’-martensitic microstructure, an α/β-microstructure containing at least 63.8% β-phase develops. Depending on the post L-PBF heat-treatment, either an increased upsetting at failure (33.9%) compared to unmodified Ti-6Al-4V (28.8%), or an exceptional high compressive yield strength (1857 ± 35 MPa compared to 1100 MPa) were measured. The hardness of the in situ alloyed material ranges from 336 ± 7 HV0.5, in as-built condition, to 543 ± 13 HV0.5 after precipitation-hardening. Hence, the range of achievable mechanical properties in dependence of the post-L-PBF heat-treatment can be significantly expanded in comparison to unmodified Ti-6Al-4V, thus providing increased flexibility for additive manufacturing of titanium parts.

scholarly journals Structure and Properties of Ti/Ti64 Graded Material Manufactured by Laser Powder Bed Fusion

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6140
Author(s):  
Evgenii Borisov ◽  
Igor Polozov ◽  
Kirill Starikov ◽  
Anatoly Popovich ◽  
Vadim Sufiiarov
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Additive Manufacturing ◽  
Hot Isostatic Pressing ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Powder Bed ◽  
Isostatic Pressing ◽  
Graded Material ◽  
Single Part

Multimaterial additive manufacturing is an attractive way of producing parts with improved functional properties by combining materials with different properties within a single part. Pure Ti provides a high ductility and an improved corrosion resistance, while the Ti64 alloy has a higher strength. The combination of these alloys within a single part using additive manufacturing can be used to produce advanced multimaterial components. This work explores the multimaterial Laser Powder Bed Fusion (L-PBF) of Ti/Ti64 graded material. The microstructure and mechanical properties of Ti/Ti64-graded samples fabricated by L-PBF with different geometries of the graded zones, as well as different effects of heat treatment and hot isostatic pressing on the microstructure of the bimetallic Ti/Ti64 samples, were investigated. The transition zone microstructure has a distinct character and does not undergo significant changes during heat treatment and hot isostatic pressing. The tensile tests of Ti/Ti64 samples showed that when the Ti64 zones were located along the sample, the ratio of cross-sections has a greater influence on the mechanical properties than their shape and location. The presented results of the investigation of the graded Ti/Ti64 samples allow tailoring properties for the possible applications of multimaterial parts.

scholarly journals Multi-Laser Powder Bed Fusion Benchmarking—Initial Trials with Inconel 625

2019 ◽  
Vol 105 (7-8) ◽  
pp. 2891-2906 ◽  
Author(s):  
H. Wong ◽  
K. Dawson ◽  
G. A. Ravi ◽  
L. Howlett ◽  
R. O. Jones ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Production Rate ◽  
Single Mode ◽  
Inconel 625 ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Powder Bed ◽  
Single Laser ◽  
Stress Relieving

Abstract Production rate is an increasingly important factor in the deployment of metal additive manufacturing (AM) throughout industry. To address the perceived low production rate of metal AM systems based on single-laser powder bed fusion (L-PBF), several companies now offer systems in which melting has been parallelised by the introduction of multiple, independently controlled laser beams. Nevertheless, a full set of studies is yet to be conducted to benchmark the efficiency of multi-laser systems and, at the same time, to verify if the mechanical properties of components are compromised due to the increase in build rate. This study addresses the described technology gaps and presents a 4-beam L-PBF system operating in “single multi” (SM) mode (SM-L-PBF) where each of the four lasers is controlled so that it melts all of a particular components’ layers and produces specimens for comparison with standard L-PBF specimens from the same machine. That is all four lasers making all of some of the parts were compared to a single-laser manufacturing all of the parts. Build parameters were kept constant throughout the manufacturing process and the material used was Inconel 625 (IN625). Stress-relieving heat treatment was conducted on As-built (AB) specimens. Both AB and heat-treated (HT) specimen sets were tested for density, microstructure, tensile strength and hardness. Results indicate that the stress-relieving heat treatment increases specimen ductility without compromising other mechanical properties. SM-L-PBF has achieved a build rate of 14 cm3/h when four 200 W lasers were used to process IN625 at a layer thickness of 30 μm. An increase in the build rate of 2.74 times (build time reduction: 63%) has been demonstrated when compared to that of L-PBF, with little to no compromises in specimen mechanical properties. The observed tensile properties exceed the American Society for Testing Materials (ASTM) requirements for IN625 (by a margin of 22 to 26% in the 0.2% offset yield strength). Average specimen hardness and grain size are in the same order as that reported in literatures. The study has demonstrated that a multi-laser AM system opens up opportunities to tackle the impasse of low build rate in L-PBF in an industrial setting and that at least when operating in single mode there is no detectable degradation in the mechanical and crystallographic characteristics of the components produced.

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