Light Metal Technology: Forming Technology
Sponsored by: TMS Titanium Committee
Program Organizers: Xiaoming Wang, Purdue University; Yufeng Zheng, University of North Texas
Monday 2:00 PM
October 18, 2021
Room: A213
Location: Greater Columbus Convention Center
Session Chair: Tao Wang, Rio Tinto
2:00 PM
Effect of Vacuum Level on Porosity and Mechanical Properties of Aluminum Alloys in High-pressure Die Casting: Nicole Trometer1; Emre Cinkilic1; Larry Godlewski2; Eben Prabhu2; Alan Luo1; 1The Ohio State University; 2Ford Motor Company
High-pressure die casting is used to produce lightweight aluminum structural parts with high specific strength. However, a common problem in these parts is entrapped gas which decreases the mechanical properties of the castings. The use of vacuum in the die casting process can reduce the amount of gas porosity. In this study, three vacuum levels were compared in process simulations and high-pressure die-cast samples of two aluminum alloys. The porosity in the die-cast samples was characterized using metallography, density measurements and CT scanning. The decrease in entrapped air and gas porosity was in agreement with the computer simulations. The mechanical properties of the samples were also tested and showed an improvement with increasing vacuum level
2:20 PM
Lattice Site Correspondence and Morphology of Al6Mn Precipitate: Yuchi Wang1; Yunzhi Wang1; Daniel Freiberg2; Yang Huo2; Wendi Zhu2; Robert Williams1; Mei Li2; 1Ohio State University; 2Ford
In 7xxx series Al alloys that contain Mn, Al6Mn is an important precipitate phase that enhances the alloy’s strength with precipitation hardening. To investigate the full three-dimensional (3D) morphology of the Al6Mn precipitate, two possible lattice site correspondences (LCs) between the two phases are derived from the experimentally observed orientation relationship and crystal structures of the two phases. A phase-field model is developed to simulate the 3D morphology of the Al6Mn precipitate as a function of size. The shapes and habit planes of the precipitates obtained under the two different LCs are compared with each other and to experimental characterizations by transmission electron microscope (TEM), which allow us to determine the correct LC and develop a better understanding of the different shapes of the Al6Mn precipitate observed at different 2D cross-sections of the TEM images.
2:40 PM
Comparison of Acoustic Softening Phenomenon in Tensile Tests and Incremental Sheet Forming: Randy Cheng1; Jiarui Kang2; Xun Liu2; Alan Taub1; 1University of Michigan; 2The Ohio State University
Tensile testing of metals with ultrasonic vibration has shown a consistent reduction in flow stress, known as acoustic softening. However, the use of ultrasonic vibrations in complex deformation processes is less efficient in transmitting acoustic energy leading to lower softening. This experimental study compares the softening behavior of AA2024-O under tensile loading and incremental sheet forming (ISF) of a groove-shaped geometry. By varying the feed rate and sheet thickness, the total imparted acoustic energy and, therefore, the acoustic energy density can also be varied. The results show that the magnitude of acoustic softening is lower in incremental sheet forming compared to tensile tests. The relationship between acoustic energy density and material softening is correlated. Microhardness measurements were conducted to compare the degree of strain hardening. Electron backscatter diffraction (EBSD) was performed to compare grain size and texture evolution.
3:00 PM
START: Rio Tinto’s ‘Nutrition Label’ for Sustainable Aluminium: Tao Wang1; 1Rio Tinto
Rio Tinto is an industry leader in sustainable aluminium products. In 2016, it launched the industry's first certified low carbon aluminium, RenewAl™. In 2018, Rio Tinto became the first company to receive the certification from the Aluminium Stewardship Initiative (ASI). In 2019, with the launch of ‘Elysis’, Rio Tinto set the goal to industrialize this revolutionary inert anode technology by 2024. Today, Rio Tinto is launching ‘START’, the new sustainable offering for the aluminium industry. START stands for Sustainability, Traceability, and Assurance from Rio Tinto. Using secure blockchain technology, START seamlessly gives customers and end users confidence about where and how the aluminium products they purchase are responsibly made, just like the nutrition label of the material. Relying on the responsible production, Rio Tinto continues to develop aluminium products with high strength, lightweight, and low carbon footprint to support different industries such as automotive, building & constructions, and packaging.