scholarly journals The Influence of Process Parameters and Build Orientation on the Creep Behaviour of a Laser Powder Bed Fused Ni-based Superalloy for Aerospace Applications

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1390 ◽  
Author(s):  
Hani Hilal ◽  
Robert Lancaster ◽  
Spencer Jeffs ◽  
John Boswell ◽  
David Stapleton ◽  
...  
Keyword(s):  
Process Parameters ◽  
Structural Integrity ◽  
Mechanical Performance ◽  
Creep Behaviour ◽  
Test Method ◽  
Influence Of Process Parameters ◽  
Powder Bed ◽  
Build Orientation ◽  
Aerospace Applications ◽  
Layer Manufacturing

Additive Layer Manufacturing (ALM) is an innovative net shape manufacturing technology that offers the ability to produce highly intricate components not possible through traditional wrought and cast procedures. Consequently, the aerospace industry is becoming ever more attentive in exploiting such technology for the fabrication of nickel-based superalloys in an attempt to drive further advancements within the holistic gas turbine. Given this, the requirement for the mechanical characterisation of such material is rising in parallel, with limitations in the availability of material processed restricting conventional mechanical testing; particularly with the abundance of process parameters to evaluate. As such, the Small Punch Creep (SPC) test method has been deemed an effective tool to rank the elevated temperature performance of alloys processed through ALM, credited to the small volumes of material utilised in each test and the ability to sample material from discrete locations. In this research, the SPC test will be used to assess the influence of a number of key process variables on the mechanical performance of Laser Powder Bed Fused (LPBF) Ni-based superalloy CM247LC. This will also include an investigation into the influence of build orientation and post-build treatment on creep performance, whilst considering the structural integrity of the different experimental builds.

scholarly journals Additive Manufacturing and Mechanical Performance of Trifurcated Steel Joints for Architecturally Exposed Steel Structures

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1901
Author(s):  
Pengfei He ◽  
Wenfeng Du ◽  
Longxuan Wang ◽  
Ravi Kiran ◽  
Mijia Yang
Keyword(s):  
Finite Element ◽  
Additive Manufacturing ◽  
Process Parameters ◽  
Mechanical Performance ◽  
Steel Structures ◽  
Mechanical Tests ◽  
Test Method ◽  
Finite Element Analyses ◽  
Steel Joint ◽  
Steel Joints

Additive Manufacturing (AM) technology has unique advantages in producing complex joints in architecturally exposed steel structures. This article focuses on the process of manufacturing and investigating the mechanical properties of a reduced scale model of a trifurcated joint using Selective Laser Melting (SLM) method and mechanical tests, respectively. The orthogonal test method was used to optimize the main AM process parameters. Then the trifurcated steel joint was printed using the optimal process parameters and treated by solid solution and aging treatment. To investigate the mechanical performance of the printed joint, an axial compression test and complimentary finite element analyses were carried out. Failure processes and failure mechanisms of the trifurcated steel joint were discussed in detail. The research results show that the preferred process parameters for printing 316L stainless steel powder are: scanning power 150 W, scanning speed 700 mm/s, and scanning pitch 0.09 mm. Using these AM parameters, trifurcated steel joints with good surface quality, geometrical accuracy and tensile strength are obtained after heat treatment. Our mechanical tests and Finite element analyses results indicate that the failure mechanism in the AM trifurcated joint are similar to those of cast steel joints. Based on these results, we conclude that the AM technology serves as a promising new way for the fabrication of joints with complex geometries.

scholarly journals Laser-based additively manufactured polymers: a review on processes and mechanical models

2020 ◽  
Vol 56 (2) ◽  
pp. 961-998
Author(s):  
Roberto Brighenti ◽  
Mattia Pancrazio Cosma ◽  
Liviu Marsavina ◽  
Andrea Spagnoli ◽  
Michele Terzano
Keyword(s):  
Process Parameters ◽  
Mechanical Performance ◽  
Selective Laser Sintering ◽  
Theoretical Models ◽  
Raw Material ◽  
Laser Source ◽  
Mechanical Resistance ◽  
Layer By Layer ◽  
Influence Of Process Parameters ◽  
Mechanical Models

Abstract Additive manufacturing (AM) is a broad definition of various techniques to produce layer-by-layer objects made of different materials. In this paper, a comprehensive review of laser-based technologies for polymers, including powder bed fusion processes [e.g. selective laser sintering (SLS)] and vat photopolymerisation [e.g. stereolithography (SLA)], is presented, where both the techniques employ a laser source to either melt or cure a raw polymeric material. The aim of the review is twofold: (1) to present the principal theoretical models adopted in the literature to simulate the complex physical phenomena involved in the transformation of the raw material into AM objects and (2) to discuss the influence of process parameters on the physical final properties of the printed objects and in turn on their mechanical performance. The models being presented simulate: the thermal problem along with the thermally activated bonding through sintering of the polymeric powder in SLS; the binding induced by the curing mechanisms of light-induced polymerisation of the liquid material in SLA. Key physical variables in AM objects, such as porosity and degree of cure in SLS and SLA respectively, are discussed in relation to the manufacturing process parameters, as well as to the mechanical resistance and deformability of the objects themselves. Graphic abstract

Manufacturing Issues and the Resulting Complexity in Modeling of Additively Manufactured Metallic Microlattices

2016 ◽  
Vol 853 ◽  
pp. 394-398 ◽  
Author(s):  
M.G. Rashed ◽  
Mahmud Ashraf ◽  
Paul Jonathan Hazell
Keyword(s):  
Numerical Simulation ◽  
Physical Properties ◽  
Structural Integrity ◽  
Mechanical Performance ◽  
Research Topic ◽  
Powder Bed ◽  
Manufacturing Defects ◽  
Service Load ◽  
3D Printed ◽  
Manufacturing Techniques

Although metallic microlattice material is a sought after research topic currently, it suffers from manufacturing defects such as micro-voids formation due to missed fusion, stemmed from the stacking-layered-fused nature of the metal powder in Powder Bed Fusion (PBF) process. These defects result in weakening of the finished part and reduced mechanical performance under service load, possibly leading to low fatigue strength, and raise serious question about 3D printed structural integrity. Numerical simulation of the built parts also becomes difficult due to irregular physical properties including geometry and anisotropic nature of mechanical properties. This paper provides an overview on the manufacturing issues and the subsequent hurdle faced in numerical simulation of metallic microlattices. While the issues in manufacturing are related to emerging additive manufacturing techniques and out of control of end users, it has been suggested that the limitations in numerical simulation can be overcome by employing advanced approaches, in both physical properties measurement and modeling.

scholarly journals Laser powder bed fusion of AA7075 alloy: Influence of process parameters on porosity and hot cracking

2020 ◽  
Vol 35 ◽  
pp. 101270 ◽  
Author(s):  
Wojciech Stopyra ◽  
Konrad Gruber ◽  
Irina Smolina ◽  
Tomasz Kurzynowski ◽  
Bogumiła Kuźnicka
Keyword(s):  
Process Parameters ◽  
Hot Cracking ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Influence Of Process Parameters ◽  
Powder Bed

Small Punch Testing of Powder Bed Direct Laser Deposits

2017 ◽  
Vol 734 ◽  
pp. 94-103 ◽  
Author(s):  
Sean Davies ◽  
Robert Lancaster ◽  
Spencer Jeffs ◽  
Gavin Baxter
Keyword(s):  
Mechanical Performance ◽  
Deformation Behaviour ◽  
Test Method ◽  
Tensile Behaviour ◽  
Cast Material ◽  
Test Technique ◽  
Material Derivative ◽  
Powder Bed ◽  
Small Punch ◽  
Direct Laser

Additive Layer Manufacturing (ALM) technologies, such as Powder Bed Direct Laser Deposition (PB-DLD), have gained increasing popularity within the aerospace industry due to the advantages they hold over conventional processing routes. Among the advantages are the ability to produce more sophisticated cross-sectional geometries, a decrease in production lead times and an improvement to the buy-to-fly ratio. However, build quality and microstructural characteristics have a dependency on the process variables such as build direction. In order to understand the influence of grain size and build orientation on tensile behaviour, the Small Punch Tensile (SPT) testing technique has been applied to variants of the nickel based superalloy C263, manufactured using the PB-DLD method. The test technique utilises miniaturised samples, requiring only small volumes of material and is therefore a desirable test method to employ. SPT testing has characterised the mechanical properties between vertically and horizontally built PB-DLD C263 in comparison with the cast material derivative. Differences in mechanical performance between each variant have been revealed and found to be associated with microstructural variations. The deformation behaviour across each material variant have been exposed by interrupted tests. SPT results have also been accompanied by fractography, fracture energy calculations along with comparisons with uniaxial data.

Additive Manufacturing of Continuous Carbon Fiber Reinforced Thermoplastic Composites: An Investigation on Process-Impregnation-Property Relationship

2020 ◽  
Author(s):  
Gongshuo Wang ◽  
Zhenyuan Jia ◽  
Fuji Wang ◽  
Chuanhe Dong ◽  
Bo Wu
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Carbon Fiber ◽  
Process Parameters ◽  
Mechanical Performance ◽  
Movement Speed ◽  
Fiber Reinforced ◽  
Influence Of Process Parameters ◽  
Continuous Carbon Fiber ◽  
Carbon Fiber Reinforced

Abstract Fused filament fabrication (FFF) is one of the most broadly used additive manufacturing technologies, which possesses the advantage of a reduction in fabrication time and cost for complex-structural parts. FFF-fabricated continuous carbon fiber reinforced thermoplastic (C-CFRTP) composites have seen their great potentials in the industry due to the extraordinary mechanical properties. However, the relationship among process parameters, impregnation percentage, and mechanical properties is still unknown, which has greatly hindered both the manufacturing and application of those advanced composite parts. For this reason, the influence of process parameters on the impregnation percentage and mechanical properties of C-CFRTP specimens has been investigated in this paper. The process-impregnation-properties relationship of FFF-fabricated C-CFRTP specimens has been revealed through theoretical analyses and experimental measurement. It could be concluded that the impregnation percentage served as the bridge connecting process parameters and mechanical properties, which would provide a great insight into the property improvement. The experimental results of microscopic measurement and mechanical tests indicated that the combination of low transverse movement speed, high nozzle temperature, and small layer thickness led to an improved impregnation percentage, which ultimately produced better mechanical properties. The findings in this work will guide the fabrication of C-CFRTP parts with excellent mechanical performance for practical engineering applications.

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