Materials Processing Fundamentals: On-Demand Poster Session
Sponsored by: TMS Extraction and Processing Division, TMS Materials Processing and Manufacturing Division, TMS: Process Technology and Modeling Committee
Program Organizers: Samuel Wagstaff, Oculatus Consulting; Alexandra Anderson, Gopher Resource; Jonghyun Lee, Iowa State University; Adrian Sabau, Oak Ridge National Laboratory; Fiseha Tesfaye, Metso Outotec Finland Oy

Monday 8:00 AM
March 14, 2022
Room: Materials Processing
Location: On-Demand Poster Hall

Phase and Microstructural Analysis of In-situ Derived Alumina-TiB2 Composites: Evangelos Daskalakis1; 1University of Leeds
     The presentation focusses on the phase and microstructural evolution in laser-ignited ceramic composite based on alumina/ titanium diboride ceramic composite, in which the precursor materials are aluminium mixed with TiO2 and B2O3. The laser ignition of Al-TiO2-B2O3 mixture triggers a highly exothermic self-sustaining aluminothermic reaction (Al+TiO2+B2O3, DH= 2,736 J/kg) in the absence of atmospheric oxygen. Consequently, a ceramic phase mixture consisting of alumina and TiB2 forms spontaneously, showing a range of morphologies of phases formed. The results of the phase microstructural analysis of the reaction products formed from the furnace-ignited and quasi-pulsed 976 nm laser-ignited (30 W maximum output) are compared. The porosity, effective density, and micro-hardness properties are compared for controlling the process parameters, namely the metallic particle size, milling time and frequency, and power density of laser for triggering the flash combustion reaction. We have also modelled the process heat flow for characterising the microstructure.

Parametric Study of Mold Electromagnetic Stirring: Effects of Load Condition and Copper Resistivity: Qilan Li1; Lifeng Zhang2; Jing Zhang2; 1University of Science and Technology Beijing; 2Yanshan University
    Except effects of the modelling difference of the actual physical model and numerical model on the accuracy of calculation results , there are other parametric factors also play a role on the model accuracy. To more precisely calculate the magnetic field distribution and magnetic intensity, a numerical model of 250 mm × 280 mm cast billet is proposed to investigate the influence of load and mold copper resistivity on the magnetic intensity inside the mold under different current intensity and stirring frequency. The distribution of magnetic intensity along mold axis was output. There are little influence of the difference of no-load condition and casting condition on magnetic intensity. But with increase of stirring frequency, the degree of influence of load condition on magnetic intensity become increasingly evident. The magnetic intensity changed more obviously while changing copper resistivity of 20 °C and 160 °C.

Effect of Laser Heat Treatment and Nitrogen Content in Shielding Gas on Precipitation of Widmanstätten Austenite in Lap Laser Welds of Duplex Stainless Steels: Yunxing Xia1; Kenshiro Amatsu1; Fumikazu Miyasaka1; Hiroaki Mori1; 1Osaka University
    Duplex stainless steel attracts attention because of its excellent mechanical properties and corrosion resistance, which characterize both the ferrite and the austenite phases. However, it’s well known that the welds are easily affected by the amount of heat input and that the performance may be deteriorated due to the imbalance of the phase. This study investigated the efficiency of laser heat treatment by laser beam, focusing on the austenite stabilizing effect of nitrogen. Adding different contents of nitrogen to the shielding gas for various lap laser welding. The effects of the two methods of promoting the precipitation of austenite and the influence on the precipitation morphology are compared. In addition, the tensile test was used to summarize the relationship between the amount of austenite precipitated and mechanical strength. After that, the Widmanstatten austenite in the laser beam welds was observed stereoscopically by etching and continuous sectioning.