Defects and Properties of Cast Metals: Poster Session
Sponsored by: TMS Materials Processing and Manufacturing Division, TMS: Solidification Committee
Program Organizers: Mark Jolly, Cranfield University; Charles Monroe, University of Alabama; Brian Thomas, Colorado School of Mines; Peter Lee, University of Manchester

Tuesday 6:00 PM
February 28, 2017
Room: Hall B1
Location: San Diego Convention Ctr

L-36: Effect of the Addition of Ce and Si on the Hot Cracking Behavior of SiMn Alloy during the Solidification Process: Zizong Zhu1; Zhiqiang Zhou1; Shengnan Zhou1; Yuchuan Ding1; 1Chongqing University
    The effect of the addition of Ce and Si on the hot cracking behavior of SiMn alloy during the solidification process has been studied respectively by scanning electron microscope with energy-dispersive spectroscopy. It was found that a large amount of graphite and SiC particles are scattered in the cracking zones of the original SiMn alloy, which results in hampering of solidification shrinkage of SiMn melt and the stress concentration around the non-metallic inclusions. A small amount addition of Ce had a positive effect on the reduction of hot cracking by grain refining and decreasing the thickness of liquid film. The addition of Si is found to be beneficial on decreasing the hot cracking markedly, which is due to the large reduction of graphite particles and the increasing of eutectic phase in the grain boundary.

L-37: Improved Wear Resistance of Hadfield Steel Through the Addition of Nb Containing Carbides: Vijay Bhatia1; Gwenaelle Proust1; Julie Cairney1; 1The University of Sydney
    High manganese steel, more commonly referred to as Hadfield steel, is an austenitic manganese steel that exhibits high toughness and wear resistance after work hardening. However, in extremely high wear applications, the wear rate can be so high that the alloy never reaches peak hardness. One proposed method to increase the wear life and take full advantage of the work hardening is to ultilise carbides within the matrix. The negative influence of carbides on toughness is a concern as Hadfield steels are normally used in high impact applications. A balance is therefore required between increasing the wear resistance and maintaining an adequate toughness for the required application. This research focuses on Fe–12.1wt.%Mn–1.2wt.%C alloys with Nb containing carbides formed in-situ. The mechanical properties including toughness and wear resistance are compared to standard Hadfield steel. Microstructural characterisation is also performed before and after failure to assess the failure mechanisms.

L-39: Influence of Different Cooling Microstructure on Surface Cracks of HSLA Steel Plate by DHCR: Banglun Wang1; 1Anhui Polytechnic University
    Hot delivery and hot charging is effective measure of energy saving and consumption reducing in iron and steel industry. However, surface cracks of steel plates produced by HCR can be found easily and frequently, which may be improved through rapid cooling of slab's surface before HCR. It has been obtained that slab's microstructure such as fine ferrite-pearlite, granular bainite, upper bainite, lower bainite, martensite, through different cooling conditions. After that, slabs were reheated to 1200℃. All specimens' properties were analysed through tensile test, optical microscope, SEM, and TEM. The results show that, combination property of lower bainite is the best: the crystal particles were fine and even, the precipitate of microalloy V and Nb was relatively small amount and even, the strength is high, the plasticity is good. Surface crack of lower bainite specimen was not found after reheating.

L-42: Solidification Path of Fe Bearing Phases in the Effect of Sr and Cooling Rate in Al-Si Hypoeutectic Alloys: Jeyakumar Manickaraj1; Anton Gorny1; Sumanth Shankar1; 1McMaster University
    Our previous study for without Sr addition in Al-Si hypoeutectic alloys had shown anomalous evolution of the θ (Al13Fe4) phase followed by the τ5 (Al15FeSi2) phase, which later transformed into the τ6 (Al9Fe2Si2) phase at lower cooling rates during solidification. In the present study of understanding this Fe bearing intermetallic phase transformation in the addition of Sr was carried out with various amounts of Si, Fe additions and cooling rates. Dissolution of the cast alloy was carried out to separate the Al matrix and residual particles. X-ray diffraction analysis on the residual particles show that addition of 0.02 wt% Sr into this alloy significantly altered the solidification path of these Fe bearing phases and resulted in the evolution of the θ phase which later transformed to τ2 (Al3FeSi) and or τ4 (Al3FeSi2) followed by the evolution of the terminal τ6 (Al9Fe2Si2) phase.