Magnesium Technology 2023: Deformation and Advanced Processing
Sponsored by: TMS Light Metals Division, TMS: Magnesium Committee
Program Organizers: Steven Barela, Terves, Inc; Aeriel Murphy-Leonard, Ohio State University; Petra Maier, University of Applied Sciences Stralsund; Neale Neelameggham, IND LLC; Suveen Mathaudhu, Colorado School of Mines; Victoria Miller, University of Florida
Tuesday 2:30 PM
March 21, 2023
Room: 30C
Location: SDCC
Session Chair: Domonkos Tolnai, Helmholtz-Zentrum Hereon; Vineet Joshi, Pacific Northwest National Laboratory
2:30 PM
Barrel Finishing of Magnesium Alloys: Nina Petersen1; Björn Wiese1; Norbert Hort1; 1Helmholtz-Zentrum Hereon
Barrel finishing is a well-established process in the industry for the targeted machining of surfaces. Especially small parts in large quantities with simple geometries can be easily machined this way. When investigating the biological behaviour of degradable magnesium implant alloys, platelets of 1 cm diameter and a thickness of slightly more than one mm are often used. Due to statistical requirements, a higher number of pieces is necessary. In addition, the geometry is comparatively simple. To ensure a certain reproducibility, all samples should also have comparatively similar surfaces. In this work, different abrasives and various process parameters are investigated to answer the question of whether barrel grinding is a viable process for producing reproducible specimens.
2:50 PM
Influence of Preforging in Extrusion as well as in Equal-channel Angle Extrusion (ECAPEX) on the Properties of Magnesium Rods: René Nitschke1; Sören Müller1; 1TU Berlin
Magnesium predominantly exhibits a hexagonal lattice structure. The anisotropic distribution of activatable slip systems often leads to crystallographic preferential orientations during forming, whereby the anisotropic crystallographic properties show up macroscopically as anisotropic mechanical properties in components. Efforts to improve materials and optimize them should not only consist of mitigating or even preventing such anisotropic component properties. There is great potential to exploit them constructively. For this purpose, a 6x3 process matrix was designed using the magnesium alloy AZ31 as an example to investigate the influence of different forging as well as forming routes on the properties of extruded round bars. Six different initial states of extrusion billets and three different extrusion dies were used, one designed for double equal channel angle extrusion (ECAPEX).Forming behavior as well as microstructure and mechanical properties were investigated. Selected examples are used to present the results and evaluate the various influencing factors.
3:10 PM
Microstructure and Properties of Wrought Mg-Gd-Y-Zn-Zr Alloy (VW94) Alloy: Joshua Caris1; Janet Meier2; Vincent Hammond3; Alan Luo2; 1Terves, LLC.; 2The Ohio State University; 3US Army Research Laboratory
LPSO forming Mg-RE-Zn alloys have attracted much interest due to high strength in the cast and wrought conditions. These alloys may find niche applications where high strength and thermal stability are desired for lightweight components. This presentation will detail the recent results of a production run Mg-Gd-Y-Zn-Zr alloy, cast and extruded at scale with 380 MPa tensile strength. Aging studies post extrusion and post forging indicate additional strengthening. Microstructure as well as extrusion and forging conditions will be linked to CALPHAD equilibrium diagrams.
3:30 PM Invited
Recent Advances in PRISMS-plasticity Software for Simulation of Deformation in Mg Alloys: Mohammadreza Yaghoobi1; Duncan Greeley1; Zhe Chen1; Tracy Berman1; John E. Allison1; Veera Sundararaghavan1; 1University of Michigan
An open-source parallel 3-D crystal plasticity finite element (CPFE) software package, PRISMS-Plasticity, is presented here as a part of an overarching PRISMS Center integrated framework. A new rate-dependent twinning-detwinning model is incorporated into the framework based on an integration point sensitive scheme to model Mg alloys. The model includes both kinematic and isotropic hardening in order to handle cyclic response of structural metals. The model is validated versus high energy diffraction microscopy (HEDM) results of Mg alloys during cyclic loadings. PRISMS-Plasticity TM is another feature which has been developed as a new open-source rapid texture evolution analysis pipeline based on the Taylor model, which is integrated into the open-source crystal plasticity software, PRISMS-Plasticity. The developed framework is used to capture the effects of alloying on texture development in Mg-Zn-Ca alloys. Finally, the PRISMS-Plasticity software has been integrated with the PRISMS-PF phase-field framework to model twinning within Mg alloys.
3:50 PM Break
4:05 PM
The Mechanisms to Improve Creep Resistance in a Die-cast MgREMnAl Alloy: Xixi Dong1; Lingyun Feng1; Eric Nyberg2; Shouxun Ji1; 1Brunel University London; 2Kaiser Aluminum
High-pressure die-cast magnesium (Mg) alloys are required for components working at temperatures above 200 °C. These new alloys are necessary for high-volume applications such as critical parts used for internal combustion (IC) engines in power tools. Here we present new developments of a Mg–RE die-cast alloy that shows excellent ambient and high temperature tensile strength, creep resistance, stiffness and thermal conductivity, which are key advantages for alloys used at elevated temperatures. The excellent creep resistance of the die-cast Mg3.5RE(La,Ce,Nd)1.5GdMnAl alloy, in comparison with its counterpart alloy without the Al addition, shows a significant improvement of the steady-state creep rate (SCR) at 300°C/50MPa. The synergistic effect of Al, Gd and Mn has been found to induce a novel and thermally stable AlMnGd ternary short-range order (SRO, 0–2nm)/cluster (2–10nm) in the Mg matrix, which is believed to be responsible for the improvement in creep performance.
4:25 PM
Solid Phase Processing of Mg-Al-Mn-Ca for High Strength and Ductility: David Garcia1; Hrishikesh Das1; Kumar Sadayappan2; Peter Newcombe2; Darrel Herling1; Glenn Grant1; Mageshwari Komarasamy1; 1Pacific Northwest National Laboratory; 2CANMET - Materials Technology Laboratory
While rare-earth Mg alloys have shown remarkable properties for high strength applications, lower cost alternatives are necessary for the widespread industry use of Mg. Ca added Mg alloys have shown promise as an alternative to rare-earth alloys. Ca-based precipitates can reduce basal texture, reduce casting porosity, and increase mechanical strength. However, the accumulation of Ca-based precipitates along inter-dendritic regions can severely limit ductility. Here, we apply two solid phase processing techniques, friction stir processing and shear assisted processing and extrusion, to produce locally modified processing region and extruded tubes, respectively in a cast Mg-Al-Mn-Ca alloy. Ductility of the alloy is enhanced by densification under applied force and elevated temperature, and refinement of (Al,Mg)-Ca based precipitates; strength improvement is attained via grain refinement, and isotropic properties via random texture.
4:45 PM
The Effects of Temperature and Strain Rate on the Tensile Behaviour of Die-cast Magnesium Alloy AE44: Trevor Abbott1; Hua Qian Ang2; Suming Zhu3; Mark Easton2; 1Magontec Limited; 2RMIT University; 3Monash University
The tensile properties and work hardening behaviour of die-cast magnesium alloy AE44 were investigated at a wide range of temperatures from 77 K to 473 K and strain rates from 10-6-10-1 s-1. AE44 was also subjected to T5 ageing to understand the effect of heat treatment on the work hardening behaviour. Both the as-cast and T5-aged AE44 showed a continuous decrease in strength and hardening rate with increasing temperatures. A positive strain-rate sensitivity was observed over the entire temperature range. Voce hardening law was used to examine the work hardening behaviour, and it appears that the athermal hardening stage previously reported for magnesium alloys, does not exist in AE44 for the studied temperatures and strain rates.