Defects and Properties of Cast Metals: Poster Session
Sponsored by: TMS Materials Processing and Manufacturing Division, TMS: Solidification Committee
Program Organizers: Lang Yuan, University of South Carolina; Brian Thomas, Colorado School of Mines; Peter Lee, University College London; Mark Jolly, Cranfield University; Alex Plotkowski, Oak Ridge National Laboratory; Charles Monroe, University of Alabama Tuscaloosa
Tuesday 5:30 PM
February 25, 2020
Room: Sails Pavilion
Location: San Diego Convention Ctr
Cancelled
M-51: Component Analysis of Defects in Secondary Special Brass Alloy: Liu Wei; Xing Peng1; Zhao Hongliang1; Wang Chengyan1; Chen Yongqiang1; Guo Shumei2; Liu Fengqin1; Huang Teng2; 1University of Science and Technology Beijing; 2Ningbo Wave Vibration Copper Co., Ltd.
The direct smelting of scrap copper to produce high-quality brass alloy not only solves the problem of municipal solid waste, but also realizes the reuse of valuable metals and alleviates the problem of copper shortage. However, impurities are not easily controlled and there are occasional defects in the surface of secondary brass products such as door handles, mechanical parts, etc. In this paper, microstructure of the defective samples was studied with scanning electron microscope (SEM), Energy Dispersive Spectrometer (EDS) and electron probe microanalyzer (EPMA). The investigation findings suggest that defects can be attributed to the formation of γ phase brass, the wrapped of refining agent or slag and the unremoved of impurity elements.
M-52: Microstructure Evolution and Chemical Composition in Continuous Directional Solidification Cu–P–Sn Alloy: Jihui Luo1; Xinxin Deng1; Li Zhang1; Suliang Wang1; Zhongfang Xie1; Xianyue Ren1; 1Yangtze Normal University
Ternary Cu–P–Sn alloy was prepared by continuous directional solidification (CDS) technique. The microstructure of CDS Cu–P–Sn alloy was analyzed by optical microscopy and field emission scanning electron microscopy. The chemical composition distribution was analyzed by energy dispersive spectrometry. The results show that the CDS Cu–P–Sn alloy has many linear structures. The linear structures are vertically arranged along the solidification direction in the longitudinal section and arranged with a disorderly manner in the transverse section. The number of linear structures also is larger in transverse section than in longitudinal section. CDS Cu–P–Sn alloy has exudation layer with lamellar structure, which has high solute contents of P and Sn.
M-53: Ni/Mn Replacement in High-Ni Austenitic Stainless Cast Steels Used for Turbo-charger: Jisung Yoo1; Won-Mi Choi1; Byeong-Joo Lee1; Yong-Jun Oh2; Gi-Yong Kim3; Sunghak Lee1; 1Pohang Institute of Science & Technology, POSTECH; 2Hanbat National University; 3Key Yang Precision
Recently, high-Ni austenitic cast steel whose brand name is a DIN 1.4849 (0.4C-2.0Mn-1.5Si-20Cr-38Ni-1.5Nb (wt.%)) has been commercially used for high-performance housings, due to its excellent strengths and thermal fatigue properties above a typical exhaust-gas temperature of 950°C. Since this steel contains 38 wt.% of Ni, a partly replacement of Ni by Mn is needed for reducing alloying costs (up to 25%) without losing high-temperature properties. When the Ni content reduces to 22 wt.%, there are no merits of high-temperature strengths as the total carbide fraction decreases. The 24%Ni-containing steel contains the highest total carbide fraction, which results in the highest high-temperature strengths. Furthermore, the initiation and propagation of microcracks are retarded by the relatively homogeneous carbide distribution due to the smallest cell size. Thus, alloy designing for enhancing the distribution and fraction of total carbides is desirable for high-temperature properties of the austenitic stainless cast steels.
M-54: Synchrotron Validated Modelling of Pore Formation During High Pressure Die Casting: Zhixuan Gong1; Shishira Bhagavath2; Tim Wigger1; Saurabh Shah1; Sebastian Marussi1; Shashidar Marathe3; Shyamprasad Karagadde2; Peter Lee1; 1University College London; 2Indian Institute of Technology Bombay; 3Diamond Light Source Ltd
High pressure die-casting (HPDC) is an efficient and low-cost production technique for aluminium alloy light-weight automotive components. However, some of the microstructural features present, such as porosity, may limit the component’s strength and fatigue life. These microstructural feature form due to the complex interaction of the high velocity liquid metal flow and deformation, combined with solidification phenomena. This study presents in situ synchrotron radiography and tomography experiments that seek to replicate the manufacturing process to enable a greater understanding of the mechanisms by which microstructural features form. In this study, we present results during the filling and intensification processes with varying processing fraction solid (~0.2-0.8) and loading rate (~30-60 μm/s). The results reveal the importance of melt flow on microstructural feature formation and were used to inform and validate a computational model developed in OpenFOAM for further process optimisation.
M-55: The Optical and Electronic Features of HgSiX2 (X=P, As) Chalcopyrite Materials: A First Principle Calculations: Khalid Shah1; Guiwu Lu1; 1China University of Petroleum-Beijing
In this study, we figured out the optical and electronic features of HgSiX2 (X=P, As) with the help of pseudo-potential plane wave approach in Castep module. Our output results showed alignment with the results drawn from the other experimental and theoretical studies. The band energy gaps, partial and total densities of states and optical properties have been calculated and elaborated. From the band structures and density of states calculated outputs, showed that these materials are semiconductors of ban gap energy equal to 0.833 eV for HgSiP2 phase and 0.425 eV for HgSiAs2 Phase, and their larger contribution is coming from Si-3p P-3p and As-4p atomic orbitals. Moreover, the comprehensive analysis of optical-functions such as reflectivity, absorption spectra, and dielectric function. These compounds are good dielectric materials. It is expected that the manufacture of HgSiP2 and HgSiAs2 devices can give new advance strategies for the explorations in high efficient optoelectronic materials.