Magnesium Technology: Characterization and Joining, Machining, and Forming
Sponsored by: TMS Light Metals Division, TMS: Magnesium Committee
Program Organizers: Petra Maier, University of Applied Sciences Stralsund; Steven Barela, Terves, Inc; Victoria Miller, University of Florida; Neale Neelameggham, IND LLC
Wednesday 8:30 AM
March 2, 2022
Room: 210A
Location: Anaheim Convention Center
Session Chair: Suveen Mathaudhu, Colorado School of Mines; Domonkos Tolnai, Helmholtz-Zentrum Hereon; Alan Luo, Ohio State University; Vineet Joshi, Pacific Northwest National Laboratory
8:30 AM
Characterization of Binary Solute Contributions to Cyclic Deformation in Magnesium Alloys by High Energy X-ray Diffraction: Duncan Greeley1; Mohammadreza Yaghoobi1; Katherine Shanks2; Darren Pagan2; Veera Sundararaghavan1; John Allison1; 1University of Michigan; 2Cornell High Energy Synchrotron Source
Magnesium is a promising material for lightweighting in the transportation industries due to its low density and high specific strength. Fatigue performance is a primary concern for structural parts, and accurate modelling of fatigue in novel magnesium alloy compositions requires a detailed understanding of the role of solutes on modification of texture, slip mode critical resolved shear strengths, and cyclic twinning-detwinning behavior. In this study, pure magnesium and Mg-4wt.%Al, Mg-7.5wt.%Y, and Mg-2.4wt.%Nd binary alloys were characterized during single cycle compression-tension displacement experiments using High Energy X-Ray Diffraction Microscopy (HEDM) at the Cornell High Energy Synchrotron Source (CHESS). The impact of binary solute additions on macroscopic and grain-scale mechanical response, full-volume twin activity, and texture evolution was investigated with a combination of far-field HEDM, near-field HEDM, and crystal plasticity finite element modelling, and the datasets are published publicly on the Materials Commons information repository.
8:50 AM Invited
To Fail or Not to Fail: Norbert Hort1; Petra Maier2; 1Helmholtz-Zentrum Hereon; 2University of Applied Sciences Stralsund
When new research topics appear, theoretical approaches are developed, predictions are made, and expectations are raised. However, experiments, modelling and simulations show often results that do not fit the expectations and the theories that were used to design the models and experiments appear to be incomplete or even wrong. These results are often regarded as “bad” results and the conclusion of a failure is drawn! This leads often to the fact that these theories and results are not published. We think that this is the wrong approach as any result is a “good” result. It is a result, which can be used for further decisions, adaption of models and experiments. Therefore, we would like to raise attention on this issue and encourage everybody to publish even “bad” results, providing their discussion. These results could be helpful in the design of research strategies or in the identification of new research areas.
9:10 AM
Microstructure Evolution of AZ31B Mg Alloy during Bi-axial Fatigue Loading: Sugrib Shaha1; Dwayne Toscano2; Hamid Jahed2; 1Georgia Institute of Technology; 2University of Waterloo
To understand the deformation behavior of AZ31B Mg alloy in biaxial loading, forged hollow cylindrical samples were tested in proportional loading in-phase and out-of-phase. The dislocation morphology, it’s activity, and interaction were investigated. The geometrically necessary dislocation (GND) density distribution was calculated using an electron backscatter diffraction (EBSD) in Nye's tensor method. TEM analysis identified the type of slip and twinning system. A relatively high density of stacking faults, basal and non-basal dislocations were identified in the failed samples. In-phase loading displays deformation through tension twinning and basal slip. In contrast, under bi-axial loading reveals dual activation of basal 〈a〉 and prismatic 〈c+a〉 dislocations in 45° out of phase loading while 90° out of phase loading exhibits an additional type of dislocation of pyramidal 〈c〉.
9:30 AM
Wire-based Additive Manufacturing of Magnesium Alloys: Stefan Gneiger1; Daniel Koutny2; Sascha Senck3; Martin Schnall1; Nikolaus Papenberg1; Thomas Klein1; 1Light Metals Technologies Ranshofen; 2Brno University of Technology; 3University of Applied Sciences Upper Austria
Additive manufacturing is experiencing a strong increase in scientific and industrial interest as well as steadily growing areas of application, as it allows the production of complex parts and revolutionizes possibilities for lightweight construction. The resulting potential can be further enhanced by using magnesium alloys. Since the mostly used additive manufacturing processes are powder-based, they involve handling of highly reactive materials and require the use of closed production chambers, especially when Mg is involved. In contrast, these problems can be avoided with wire-based additive manufacturing methods. Additionally, higher deposition rates can be achieved. Here, wire-based additive manufacturing utilizing the Cold Metal Transfer process (CMT) is used to demonstrate the feasibility of processing a magnesium alloy suitable for use in structural applications. Characterization of the fabricated structures was performed, and the results of the microstructural- and mechanical investigations are presented here.
9:50 AM Break
10:10 AM
Nanomechanical Analysis and Fractography of Extruded Mg-Dy-Nd Based Alloy Influenced by Solution Heat Treatment: Petra Maier1; Asta Richter2; Benjamin Clausius1; Norbert Hort3; 1University of Applied Sciences Stralsund; 2University of Applied Sciences Wildau; 3Helmholtz-Zentrum Hereon
This study concentrates on nanomechanical analysis and fractography of an extruded Mg-Dy-Nd-Zn-Zr alloy in different microstructures. The focus here lies on the reduced elastic modulus evaluated from nanoindentaion and the fracture behavior evaluated by SEM. The initial hot-extruded condition shows a fine-grained microstructure consisting of lamellar LPSO within the matrix and blocky LPSO-phases and precipitates. Solution heat treatment causes grain growth and dissolution of the LPSO phases and precipices, the matrix becomes enriched by solid solution. Except for the blocky LPSO in the extruded microstructure, where the value is higher, the reduced elastic modulus does not change across the microstructural features. C-ring compression tests in Ringer solution were used to evaluate the fracture behavior, mostly transgranular cleavage facets with some ductile features are present. The amount sub-cracks forming from the main crack are influenced by the heat treatment time. Blocky LPSO do not show very present on the fracture surface.
10:30 AM
Dissimilar Metal Micro Friction Stir Welding of Magnesium AZ31 to Aluminum 6061: Eisha Khalid1; Vasanth Shunmugasamy1; Bilal Mansoor1; 1Texas A&M University at Qatar
As the trend of miniaturization and light-weighting of structures is increasing, the demand for micro-scale welding processes is increasing for applications like electronic packaging, micro-electro-mechanical systems, energy storage devices, and the aerospace industry. In this context, we are investigating micro friction stir welding (micro-FSW), an adaptation of friction stir welding for joining and processing of similar and dissimilar materials with thicknesses of 1 mm and below. As part of the current research, we have attempted to butt weld AZ31 and Al6061 thin sheets < 1 mm. Our initial results are promising and here we report on the defect-free weldment, microstructure, and mechanical properties of the weld.
10:50 AM
Friction Stir Extrusion of AZ31 Magnesium Alloy Rod: Maryam Al-Buainain1; Vasanth Shunmugasamy2; Bilal Mansoor2; 1Texas A&M University; 2Texas A&M University at Qatar
Magnesium and its alloys are lightweight and biodegradable – properties that are attractive for structural applications in transportation and biomedical sectors. Mg has an HCP crystal structure that limits the room temperature formability, necessitating multi-stage high-temperature processing steps. In this context, we have used Friction Stir Extrusion (FSE), a severe plastic deformation process, to fabricate some basic structural building blocks such as rods and tubes. In FSE, heat input is obtained through friction between a rotating, rubbing tool and workpiece, forging and severe plastically deformation the material to the desired shape in a single step. This research utilizes commercially available AZ31 Mg alloy to prepare structural building blocks such as rods and tubes. FSE assists in engineering the microstructure of the prepared components, enabling control over its mechanical response. We will present our initial findings of the properties of the FSE processed AZ31 and how grain size and texture influence them.
11:10 AM
Determining the Contributions of Dynamic Recrystallization and Deformation Mechanisms to the Weak Textures Observed in As-deformed Mg-Zn-Ca Alloys: Tracy Berman1; Mohammadreza Yaghoobi1; John Allison1; 1University of Michigan
Alloying and processing both affect microstructure and therefore development of formable Mg sheet alloys requires knowledge of the interplay of these variables. Rolling is a complex process consisting of several rolling passes separated by annealing, this results in a microstructure that can potentially have contributions from both dynamic and static recrystallization (RX). The active deformation mechanisms will influence the texture as well. This study utilizes plane strain compression tests conducted in a Gleeble thermomechanical processing (TMP) simulator, coupled with crystal plasticity simulations to isolate the contributions of dynamic recrystallization (DRX) and deformation activity on the texture evolution that occur during deformation of Mg-Zn-Ca alloys.