Additive Manufacturing of Metals: Establishing Location-Specific Processing-Microstructure-Property Relationships: Aerospace and Aluminum Alloys
Sponsored by: TMS Materials Processing and Manufacturing Division, TMS: High Temperature Alloys Committee, TMS: Shaping and Forming Committee, TMS: Additive Manufacturing Bridge Committee
Program Organizers: Eric Lass, NIST; Judy Schneider, University of Alabama-Huntsville; Mark Stoudt, National Institute of Standards and Technology; Lee Semiatin, AFRL; Kinga Unocic, Oak Ridge National Laboratory; Joseph Licavoli, Michigan Technological University; Behrang Poorganji, YTC America Inc.

Thursday 8:30 AM
March 2, 2017
Room: 7B
Location: San Diego Convention Ctr

Session Chair: Behrang Poorganji, YTC America Inc.; Kenta Yamanaka, Tohoku University

8:30 AM  Invited
Alcoa Additive Manufacturing: A Revolution in the Making: John Barnes1; Chris Aldridge1; 1Alcoa
    The aerospace market is one of the leading industries embracing Additive Manufacturing for real production parts. Alcoa is an established innovation leader in aerospace and 3D printing, with unique and comprehensive capabilities from raw material to finished part. In this presentation, the current state of the art of additive manufacturing in metal will be described with a view on where it is going from a vertically integrated supply chain solution. The components of this advancement has to be leveraged from structure, materials and manufacturing which has to be fueled by innovation and increasingly through engagement with people. The critical role of materials will be highlighted as will design freedoms afforded by additive manufacturing, the cost & weight savings AM parts can deliver to the aerospace market and thru-put and speed considerations for production parts.

9:00 AM  
Evolution of Aluminum Alloys Structure at Production Phases of 3D Products by Methods of Additive Technologies: Ivan Redkin1; Victor Mann1; Aleksandr Krokhin1; Aleksandr Alabin1; Sergey Zmanovskiy1; Valentin Konkevich1; 1RUSAL Global Management B. V.
    The structure and phase structure of an aluminum alloy type Al10SiMg, received in the conditions of classical molding castings and the 3d printing by selective laser melting is investigated. Consistent patterns of redistribution of the alloying elements in structure in the course of powder production, the 3D printing and the subsequent heat treatment are determined. The analysis of mechanical properties level of the samples received on 3d technology in comparison with castings is carried out. On the basis of the received regularities, the new compositions on the basis of aluminum, providing a combination of high level of mechanical and physical characteristics for 3d products are offered. Purpose of new materials for 3d printing - critical parts operating under high loads for application in transport products, in particular the automotive and aircraft industry.

9:20 AM  
Characterization of Multiperforated Plates Manufactured by SLM and EBM for Aeroengine Applications: Marc Thomas1; Océane Lambert1; Cécile Davoine1; Fabienne Popoff1; Corinne Dupuy2; Patrice Peyre2; Rémy Dendievel3; 1ONERA; 2ENSAM ParisTech; 3SIMaP
    Additive Manufacturing has shown growing interest in the last years compared to traditional techniques for aeronautical complex shaped parts. In this context, the development of multiperforated plates by additive techniques such as Selective Laser Melting and Electron Beam Melting with respect to conventional substractive technique by laser drilling can be promising for combustion chamber applications. Multiperforated plates have then been manufactured by SLM at ENSAM ParisTech and by EBM at SIMaP to provide efficient cooling system within the chamber. The present work has been focused on the detailed analysis of these different plates, including microstructural characterization, permeability measurements and the assessment of surface roughness from X-ray tomography and subsequent image analysis. A special attention was paid to the surface roughness since this parameter might be beneficial for an increasing heat transfer surface, but also might be deleterious for the film cooling stability because of the onset of turbulent regimes.

9:40 AM  Cancelled
The Effect of Heat Treatments and Micro-mechanism Investigation on Anisotropic Creep and Low Cycle Fatigue properties of IN718 Processed by Selective Laser Melting: Changpeng Li1; Guofeng Chen1; Zhiqi Yao1; Zhongjiao Zhou2; 1Corporate Technology, Siemens; 2Tsinghua University
    The anisotropic creep and fatigue properties remain a big concern for the application of additive manufacturing in the critical components of aerospace and power generation equipments. In this presentation, the nickel-based superalloy IN718 samples were processed via selective laser melting (SLM) technology (EOS M280), with different orientations relative to the building direction, to investigate the anisotropy of SLMed components. In addition, three variants of heat treatments were accepted, i.e. (1) solution + aging (SA); (2) homogenization + aging (HA) and (3) homogenization + solution + aging (HSA). The influence of sample orientations and post heat treatments were systematically investigated via creep and low cycle fatigue tests under 650oC. Together with the thorough examination of precipitate phases, microstructures, and fracture surface using OM, SEM, EBSD, EDX, TEM and X-ray analysis methods, the micro-mechanism and modeling were developed for the guidance of property optimization.

10:00 AM Break

10:20 AM  
Emerging High-strength Aluminum Alloys for Selective Laser Melting: Todd Mower1; Jason Jones2; 1MIT Lincoln Laboratory; 2Moog Inc.
    AlSi10Mg, the most widely used aluminum alloy produced using laser-fusion methods, has been shown by researchers to have lower fatigue strength and ductility than wrought Al6061, the most common aluminum alloy used by aerospace designers. Seeking new, higher-strength alloys produced with selective laser melting (SLM), this study explored two new aluminum alloys: Scalmalloy, a recent commercially available material with Scandium as the major alloying element; and a new, still proprietary material based upon Al7050. Tensile deformation behavior and fatigue strength of Scalmalloy specimens were measured with specimens subjected to “standard” hot isostatic pressing. Process parameters were developed to fuse the new Al7050 material with SLM, producing low-porosity specimens that were examined microscopically and tested with instrumented indentation following thermal treatments to stimulate precipitation hardening.

10:40 AM  
AlSi10Mg Lattice Structures Processed by Selective Laser Melting: Influence of the Geometry and the Heat Treatments on the Microstructure: Pauline Delroisse1; Olivier Rigo2; Pascal Jacques1; Aude Simar1; 1Université Catholique de Louvain; 2Sirris
    Lattice structures are lightweight materials widely used in the aeronautical fields for their high mechanical performances. More and more optimized thanks to the new additive manufacturing technologies, the lattice properties are strongly influenced by their process, geometry and post treatment. The objective of this project is to compare the macro and microstructure of AlSi10Mg lattice and bulk materials. Both structures are created by selective laser melting with similar parameters. Due to the fineness of the lattice parts and their 35.5° orientation during the process, a specific thermal history appears in the lattice, inducing heterogeneities in microstructure and hardness. More specifically, an heterogeneity in the dendrite arm spacing between the top and bottom of the strut is observed. EBSD analyses also highlight the specific crystallographic orientation of both geometries. In addition, the influence of heat treatment performed at different temperatures reveals that microstructure heterogeneities are erased in these samples.

11:00 AM  
Porosity Determination in Powder Bed Aluminum Alloy: Lisa Deibler1; Jay Carroll1; Jeff Rodelas1; 1Sandia National Laboratories
    Mechanical testing of laser powder bed manufactured AlSi10Mg has revealed large scatter in properties, particularly in ductility measurements during tensile tests. The observed behavior is indicative of flaw-dominated failure. The microstructural characteristics and the defect distribution in post-failure tensile bars has been characterized using fractographic and metallographic techniques and was found to be dominated primarily by porosity. Characterization of porosity is a seemingly simple task, but performing it on a scale that is useful during production of a part requires some ingenuity. The defect data has been statistically treated and linked to the mechanical properties of each particular sample. This work will be applied to determine the most effective way to monitor porosity during production.

11:20 AM  
Understanding the Columnar-to-Equiaxed Transition in Additive Manufacturing: Mark Easton1; Dong Qiu1; Mitesh Patel1; Gui Wang2; Milan Brandt1; David StJohn2; 1Royal Melbourne Institute of Technology University; 2University of Queensland
    Typically, additively manufactured alloys have a columnar grain structure. This may be due to either the AM process, where large temperature gradients tend to encourage the formation of columnar grains; or the alloys, where typically used alloys such as Ti6Al4V have low solute that does not generate constitutional supercooling and consequently does not favor equiaxed grain formation. This paper investigates how laser surface remelting affects the grain structure of cast Al-Cu, and Al-Si alloys with and without the addition of Al-Ti-B grain refiner additions. Laser remelting of the alloys without grain refiner additions led to large grains with very fine dendrite arms in the re-melted region. However, when grain refiner was added very fine equixed or mixed columnar-equiaxed zones were observed. Typically slower laser scan speeds led to a more equiaxed structure as did higher alloy contents.

11:40 AM  
Direct Laser Metal Deposition of Eutectic Al-Si Alloy for Automotive Applications: Amrinder Singh1; Abhishek Ramakrishnan1; Guru Dinda1; 1Wayne State University
    Various additive manufacturing techniques have been able to manufacture Al-Si hypo- and hyper- eutectic alloys but practical implementation of additive manufacturing of Al-Si alloys in automotive industry still remains a big challenge. This paper deals with the challenges of building tall wall and cuboid shapes eutectic Al-Si components by direct laser metal deposition technique for automotive applications. Microstructural investigation using optical and scanning electron microscopy revealed a 99.9 % dense component with very fine hypoeutectic microstructure. Tensile test showed an impressive elongation of 9 % with an ultimate tensile strength of 225 MPa. This investigation revealed that direct laser metal deposition could be successfully implemented on automotive shock tower hood without any distortion or bending. This paper also presents the effect of various laser deposition parameters like laser power, powder flow rate, and scanning speed on the microstructure and mechanical properties distribution from substrate to deposit.