Light Metal Technology: Magnesium and Joining Technology
Sponsored by: TMS Titanium Committee
Program Organizers: Xiaoming Wang, Purdue University; Yufeng Zheng, University of North Texas
Monday 10:00 AM
October 18, 2021
Room: A213
Location: Greater Columbus Convention Center
Session Chair: Yufeng Zheng, University of North Texas
10:00 AM
Now On-Demand Only - Diffusion Bonding of Aluminum by applying oscillating Pressure: Martin Salge1; Felix Gemse1; Steffen Dahms1; 1Günter-Köhler-Institute GmbH
Stable oxide layers of lightweight materials like Aluminum- and Titanium based alloys are a major challenge for diffusion bonding, as it requires atomic contact between the materials to ensure grain boundary migration and grain growth across the initial interface. High quality surfaces which are needed for good joint properties are usually achieved by mechanical or chemical removing of oxides, thus requiring longer process times compared to other materials.We present a new approach to remove oxide layers in-situ by using an oscillating pressure for the bonding of AlMg3. The additional shear stresses induced into the oxide layers in combination with the elevated temperature lead to higher joint quality, joint strength and lower thermomechanical load during the bonding process, compared to statically bonded specimens. Therefore, joint qualities equal to “classic” diffusion bonding can be achieved at reduced process temperature, pressure and cycle time, increasing efficiency and productivity of the bonding process.
10:20 AM
ECAP Strain Path Effect on Microstructure, Texture, and Mechanical Properties Evolution in Pure Magnesium: Prakash Gautam1; Somjeet Biswas2; 1India Institute of Technology Kharagpur; 2IIT Kharagpur
Lightweight Magnesium (Mg) alloys have the suitable potential to be utilized as structural components for automobile and aerospace application. However, the major drawback is its poor strength and formability. Equal channel angular pressing (ECAP) is a widely known severe plastic deformation technique to obtain ultrafine grains to improve these properties. In this work, Mg was deformed by ECAP via route A, BC, and C up to the 8th pass. The role of the changes in strain path during ECAP via these different routes on the microstructure and texture evolution was investigated. The visco-plastic self-consistent model was used to simulate the texture and understand the deformation mechanism for the different ECAP routes. The effect of strain path change on the strain hardening behaviour and mechanical properties were comprehended.
10:40 AM
Modeling and Study of the Effect of High Cooling Rates during Crystallization on the Structure and Properties of the Mg-Zr-Nd Alloy Used for Implants: Nikita Aikin1; Vadim Shalomeev1; 1Zaporozhye National Technical University
The work is devoted to the study of the influence of high cooling rates on the structure formation and mechanical properties of the biosoluble Mg-Zr-Nd alloy used for the manufacture of biosoluble implants. It was determined that the ultrahigh cooling rate (about 55 oC/sec), leads to the formation of superfine structure and even distribution of strengthening phases significantly improving the mechanical properties of the alloy. Based on the data of microstructure simulation, a regression equation was constructed, which allows to predict the average grain size of the alloy. The obtained empirical dependences allow to predict and obtain the final alloy with a wide range of possible mechanical properties, favorable for performing various tasks facing biosoluble implants and using the most available casting methods. Industrial-grade biosoluble implants have been preclinically tested and recommended for further use.
11:00 AM
Ultrasonic Effects on Plastic Deformation Behavior of AA2024: Jiarui Kang1; Randy Cheng2; Xun Liu1; Alan Taub2; 1The Ohio State University; 2University of Michigan
Plastic behavior of aluminum alloy 2024 under the influence of ultrasonic vibration is studied with micro-tensile tests. The gauge length of the specimen is designed one order of magnitude smaller than the wavelength of ultrasonic vibration. With this configuration, reduction of flow stress is observed as ultrasonic vibration is applied. The softening effect is more significant with increasing ultrasonic amplitude. Digital image correlation (DIC) analysis shows a change in strain distribution when ultrasonic vibration is applied. Electron backscatter diffraction (EBSD) characterization was performed to understand the ultrasonic effects on microstructural evolution and its relationship to the observed mechanical behavior.