Light Metal Technology: On-Demand Oral Presentations
Sponsored by: TMS Titanium Committee
Program Organizers: Xiaoming Wang, Purdue University; Yufeng Zheng, University of North Texas
Friday 8:00 AM
October 22, 2021
Room: On-Demand Room 12
Location: MS&T On Demand
Surface Modification of Steel Shells to Reduce the Use of Release Agents in Twin Roll Casting of Aluminum Alloys: Martin Lauth1; Alexander Nienhaus2; Hanno Paschke3; Mirko Schaper1; Olexandr Grydin1; 1University of Paderborn; 2TU Braunschweig; 3Fraunhofer Institute
Twin-roll casting of aluminum alloys always relies on the use of release agents, usually based on water-based graphite emulsions. Various surface modifications were carried out to reduce or even eliminate the use of release agents as well as to increase the service life of the steel shells. This was performed on samples with Boron diffusion treatment and also on ternary, quaternary and quinary systems like TiBN, TiBCN, TiSiBCN. PVD and PECVD processes were chosen to achieve thin and hard coating layers that prevent aluminum residues from adhering to the shells. Furthermore, hot roll bonding and aluminum droplet application)2 were used to evaluate the efficiency of the surface treatment. In this way, the most efficient surface modifications were identified that resulted in better product surface quality and lower shell resurfacing costs due to a longer life to reconditioning.
EPSC Model with Back Stress Development to Capture Multi-strain-path Behavior of AA6016-T4: Rishabh Sharma1; Dane Sargeant1; Sowmya Daroju2; Marko Kenezevic2; Michael Miles1; David Fullwood1; 1Brigham Young University; 2University of New Hampshire
The development of internal stresses during forming causes deformation behavior and final geometry characteristics that are hard to predict using conventional models. Such stresses can manifest in the Bauschinger effect, springback, and residual stresses. A recently developed elastoplastic self-consistent (EPSC) model incorporates internal stresses to accurately simulate the material response. To-date it has been employed to model cyclical loading and deep drawing of AA6022-T4. The current study assesses the performance of an EPSC model for deformation via uniaxial, plane, and biaxial strain paths in AA6016-T4. The response to strain paths was examined by pre-straining under tension, biaxial and plane-strain loading conditions, followed by uniaxial tension. The predictions closely matched experimental results. Furthermore, geometrically necessary dislocation density in the experimental specimens was compared with EPSC predicted dislocation evolution. The inclusion of internal stresses in the model led to successful prediction of hardening in AA6016-T4 samples upon a change in strain path.
In-situ Observation the Growth of Fe-rich Phases during Al Alloys Solidification: Yuliang Zhao1; 1Dongguan University of Technology
The sharp-edge Fe-rich intermetallic phases deteriorate the mechanical properties of recycled Al alloys, many attempts, such as alloy elements, grain refinement and cooling rate, have been made to modify the morphology of these phases. In this presentation, synchrotron X-ray radiography had been used to in-situ observation the growth dynamic of Fe-rich phases in Al alloys during solidification. The results showed that Al-5Ti-1B grain refiner, as well as the cooling rate, both reduced the size and number of primary Fe-rich phases. Ti-containing solutes in the melts inhibit the diffusion of Fe atoms and the Al3Fe twins produce re-entrant corner on the twin boundaries along the growth direction. Moreover, the TiB2 provides possible nucleation sites for Al6Fe phases. Also, high cooling rate inhibit the growth of primary Fe-rich phases. This study provide visible evidence to clarify insight into the nucleation and growth mechanisms of Fe-rich phases influenced by Al-5Ti-1B and cooling rate.