scholarly journals Influence of Microstructure and Defects on Mechanical Properties of AISI H13 Manufactured by Electron Beam Powder Bed Fusion

2021 ◽  
Author(s):  
Moritz Kahlert ◽  
Florian Brenne ◽  
Malte Vollmer ◽  
Thomas Niendorf
Keyword(s):  
Mechanical Properties ◽  
Electron Beam ◽  
Additive Manufacturing ◽  
Internal Cooling ◽  
Layer By Layer ◽  
Powder Bed Fusion ◽  
Powder Bed ◽  
Cooling Channels ◽  
Fine Grained ◽  
Aisi H13

AbstractElectron beam powder bed fusion (E-PBF) is a well-known additive manufacturing process. Components are realized based on layer-by-layer melting of metal powder. Due to the high degree of design freedom, additive manufacturing came into focus of tooling industry, especially for tools with sophisticated internal cooling channels. The present work focuses on the relationships between processing, microstructure evolution, chemical composition and mechanical properties of a high alloyed tool steel AISI H13 (1.2344, X40CrMoV5-1) processed by E-PBF. The specimens are free of cracks, however, lack of fusion defects are found upon use of non-optimized parameters finally affecting the mechanical properties detrimentally. Specimens built based on suitable parameters show a relatively fine grained bainitic/martensitic microstructure, finally resulting in a high ultimate strength and an even slightly higher failure strain compared to conventionally processed and heat treated AISI H13.

scholarly journals On the Impact of Build Envelope Sizes on E-PBF Processed Pure Iron

2021 ◽  
Author(s):  
C. J. J. Torrent ◽  
P. Krooß ◽  
T. Niendorf
Keyword(s):  
Mechanical Properties ◽  
Electron Beam ◽  
Additive Manufacturing ◽  
Thermal History ◽  
Powder Bed Fusion ◽  
Parameter Setting ◽  
Powder Bed ◽  
History Of ◽  
Specific Temperature ◽  
The Impact

AbstractIn additive manufacturing, the thermal history of a part determines its final microstructural and mechanical properties. The factors leading to a specific temperature profile are diverse. For the integrity of a parameter setting established, periphery variations must also be considered. In the present study, iron was processed by electron beam powder bed fusion. Parts realized by two process runs featuring different build plate sizes were analyzed. It is shown that the process temperature differs significantly, eventually affecting the properties of the processed parts.

scholarly journals Hybrid additive manufacturing of hot working tool steel H13 with dissimilar base bodies using Laser-based Powder Bed Fusion

2021 ◽  
Vol 1135 (1) ◽  
pp. 012012
Author(s):  
Lukas Langer ◽  
Matthias Schmitt ◽  
Jaime Cuesta Aguirre ◽  
Georg Schlick ◽  
Johannes Schilp
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Tool Steel ◽  
Hot Working ◽  
Powder Bed Fusion ◽  
Powder Bed ◽  
Post Process ◽  
Aisi H13 ◽  
Bonding Zone ◽  
Free Material

Abstract Hybrid additive manufacturing (HAM) describes the combination of additively built structures onto a conventionally manufactured base body. The advantages of both manufacturing processes are combined in one process chain. As a result, new applications can be achieved with higher cost-effectiveness. With the Additive Manufacturing (AM) process a bonding zone is created that is comparable to a welded joint. In order to evaluate the quality and mechanical properties of the bonding zone, two steels (42CrMo4 and 25CrMo4) are investigated as base body materials with the hot working tool steel X40CrMoV5-1 (AISI H13) for the AM structure. Process parameters for Laser-based Powder Bed Fusion of X40CrMo4V5-1 are developed to achieve a crack and defect free structure as well as an optimized bonding zone in dependency of the base body material. Furthermore, the chemical and mechanical properties are examined in the as-built and heat-treated state. It is observed that a crack-free material bonding is possible and samples with relative densities above 99.5% are obtained. The size of the bonding zone depends on the material of the base body as well as post-process heat treatment. An average hardness of 600 HV1 can be achieved in the “as-built” state.

scholarly journals Quasi-Static Tensile Properties of Unalloyed Copper Produced by Electron Beam Powder Bed Fusion Additive Manufacturing

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2932
Author(s):  
Prithwish Tarafder ◽  
Christopher Rock ◽  
Timothy Horn
Keyword(s):  
Mechanical Properties ◽  
Electron Beam ◽  
Additive Manufacturing ◽  
Tensile Test ◽  
Vacuum Annealing ◽  
Grain Morphology ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Powder Bed Fusion ◽  
Powder Bed

Mechanical properties of powder bed fusion processed unalloyed copper are reported majorly in the as-fabricated condition, and the effect of post-processes, common to additive manufacturing, is not well documented. In this study, mechanical properties of unalloyed copper processed by electron beam powder bed fusion are characterized via room temperature quasi-static uniaxial tensile test and Vickers microhardness. Tensile samples were extracted both perpendicular and parallel to the build direction and assigned to three different conditions: as-fabricated, hot isostatic pressing (HIP), and vacuum annealing. In the as-fabricated condition, the highest UTS and lowest elongation were obtained in the samples oriented perpendicular to the build direction. These were observed to have clear trends between sample orientation caused primarily by the interdependencies between the epitaxial columnar grain morphology and dislocation movement during the tensile test. Texture was insignificant in the as-fabricated condition, and its effect on the mechanical properties was outweighed by the orientation anisotropy. The fractographs revealed a ductile mode of failure with varying dimple sizes where more shallow and finely spaced dimples were observed in the samples oriented perpendicular to the build direction. EDS maps reveal that grain boundary oxides coalesce and grow in HIP and vacuum-annealed specimens which are seen inside the ductile dimples and contribute to their increased ductility. Overall, for the post-process parameters chosen in this study, HIP was observed to slightly increase the sample’s density while vacuum annealing reduced the oxygen content in the specimens.

scholarly journals Hybrid Electron Beam Powder Bed Fusion Additive Manufacturing of Ti–6Al–4V: Processing, Microstructure, and Mechanical Properties

2022 ◽  
Author(s):  
R. Tosi ◽  
E. Muzangaza ◽  
X. P. Tan ◽  
D. Wimpenny ◽  
M. M. Attallah
Keyword(s):  
Mechanical Properties ◽  
Electron Beam ◽  
Additive Manufacturing ◽  
Powder Bed Fusion ◽  
Powder Bed ◽  
Bonding Performance ◽  
Microstructure And Mechanical Properties ◽  
Basic Understanding ◽  
Hybrid Concept ◽  
Integrated Or

AbstractProcessing, microstructure, and mechanical properties of the hybrid electron beam powder bed fusion (E-PBF) additive manufacturing of Ti–6Al–4V have been investigated. We explore the possibility of integrating the substrate as a part of the final component as a repair, integrated, or consolidated part. Various starting plate surface conditions are used to understand the joining behavior and their microstructural properties in the bonding region between the plate and initial deposited layers. It is found that mechanical failures mainly occur within the substrate region due to the dominant plastic strains localized in the weaker Ti–6Al–4V substrate. The hybrid concept is successfully proven with satisfactory bonding performance between the E-PBF build and substrate. This investigation improves the practice of using the hybrid E-PBF additive manufacturing technique and provides basic understanding to this approach.

scholarly journals A Critical Review on Effect of Process Parameters on Mechanical and Microstructural Properties of Powder-Bed Fusion Additive Manufacturing of SS316L

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6527
Author(s):  
Meet Gor ◽  
Harsh Soni ◽  
Vishal Wankhede ◽  
Pankaj Sahlot ◽  
Krzysztof Grzelak ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Process Parameters ◽  
Heating Temperature ◽  
Detailed Comparison ◽  
Process Parameter ◽  
Layer By Layer ◽  
Powder Bed Fusion ◽  
Powder Bed ◽  
Practical Applications

Additive manufacturing (AM) is one of the recently studied research areas, due to its ability to eliminate different subtractive manufacturing limitations, such as difficultly in fabricating complex parts, material wastage, and numbers of sequential operations. Laser-powder bed fusion (L-PBF) AM for SS316L is known for complex part production due to layer-by-layer deposition and is extensively used in the aerospace, automobile, and medical sectors. The process parameter selection is crucial for deciding the overall quality of the SS316L build component with L-PBF AM. This review critically elaborates the effect of various input parameters, i.e., laser power, scanning speed, hatch spacing, and layer thickness, on various mechanical properties of AM SS316L, such as tensile strength, hardness, and the effect of porosity, along with the microstructure evolution. The effect of other AM parameters, such as the build orientation, pre-heating temperature, and particle size, on the build properties is also discussed. The scope of this review also concerns the challenges in practical applications of AM SS316L. Hence, the residual stress formation, their influence on the mechanical properties and corrosion behavior of the AM build part for bio implant application is also considered. This review involves a detailed comparison of properties achievable with different AM techniques and various post-processing techniques, such as heat treatment and grain refinement effects on properties. This review would help in selecting suitable process parameters for various human body implants and many different applications. This study would also help to better understand the effect of each process parameter of PBF-AM on the SS316L build part quality.

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.

A printability assessment framework for fabricating low variability nickel-niobium parts using laser powder bed fusion additive manufacturing

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Bing Zhang ◽  
Raiyan Seede ◽  
Austin Whitt ◽  
David Shoukr ◽  
Xueqin Huang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Uncertainty Quantification ◽  
Process Optimization ◽  
Powder Bed Fusion ◽  
Assessment Framework ◽  
Laser Powder Bed Fusion ◽  
Content Type ◽  
Powder Bed ◽  
Analytical Thermal Model

Purpose There is recent emphasis on designing new materials and alloys specifically for metal additive manufacturing (AM) processes, in contrast to AM of existing alloys that were developed for other traditional manufacturing methods involving considerably different physics. Process optimization to determine processing recipes for newly developed materials is expensive and time-consuming. The purpose of the current work is to use a systematic printability assessment framework developed by the co-authors to determine windows of processing parameters to print defect-free parts from a binary nickel-niobium alloy (NiNb5) using laser powder bed fusion (LPBF) metal AM. Design/methodology/approach The printability assessment framework integrates analytical thermal modeling, uncertainty quantification and experimental characterization to determine processing windows for NiNb5 in an accelerated fashion. Test coupons and mechanical test samples were fabricated on a ProX 200 commercial LPBF system. A series of density, microstructure and mechanical property characterization was conducted to validate the proposed framework. Findings Near fully-dense parts with more than 99% density were successfully printed using the proposed framework. Furthermore, the mechanical properties of as-printed parts showed low variability, good tensile strength of up to 662 MPa and tensile ductility 51% higher than what has been reported in the literature. Originality/value Although many literature studies investigate process optimization for metal AM, there is a lack of a systematic printability assessment framework to determine manufacturing process parameters for newly designed AM materials in an accelerated fashion. Moreover, the majority of existing process optimization approaches involve either time- and cost-intensive experimental campaigns or require the use of proprietary computational materials codes. Through the use of a readily accessible analytical thermal model coupled with statistical calibration and uncertainty quantification techniques, the proposed framework achieves both efficiency and accessibility to the user. Furthermore, this study demonstrates that following this framework results in printed parts with low degrees of variability in their mechanical properties.

scholarly journals Effects of Positioning Conditions on Material Properties In Powder bed Fusion Additive Manufacturing

2021 ◽  
Author(s):  
Mevlüt Yunus Kayacan ◽  
Nihat Yılmaz
Keyword(s):  
Additive Manufacturing ◽  
Material Properties ◽  
Layer By Layer ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Cooling Rates ◽  
Powder Bed ◽  
Manufacturing Technologies ◽  
Average Size ◽  
Hardness Values

Abstract Among additive manufacturing technologies, Laser Powder Bed Fusion (L-PBF) is considered the most widespread layer-by-layer process. Although the L-PBF, which is also called as SLM method, has many advantages, several challenging problems must be overcome, including part positioning issues. In this study, the effect of part positioning on the microstructure of the part in the L-PBF method was investigated. Five Ti6Al4V samples were printed in different positions on the building platform and investigated with the aid of temperature, porosity, microstructure and hardness evaluations. In this study, martensitic needles were detected within the microstructure of Ti6Al4V samples. Furthermore, some twins were noticed on primary martensitic lines and the agglomeration of β precipitates was observed in vanadium rich areas. The positioning conditions of samples were revealed to have a strong effect on temperature gradients and on the average size of martensitic lines. Besides, different hardness values were attained depending on sample positioning conditions. As a major result, cooling rates were found related to positions of samples and the location of point on the samples. Higher cooling rates and repetitive cooling cycles resulted in microstructures becoming finer and harder.

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