Mechanical Engineering
Materials Science & Engineering

TMS 2008 137th Annual Meeting & Exhibition

March 9-13, 2008

The conference held in New Orleans, LA was attended by:

2008 TMS President

Prof. Diran Apelian, Director of WPI's Metal Processing Institute, became the new TMS President for 2008. Diran Apelian is Howmet Professor of Engineering and director of the Metal Processing Institute (MPI) at Worcester Polytechnic Institute, where he has worked for more than 15 years. Professor Apelian's research interests and expertise are in materials processing, and specifically, solidification and net-shape manufacturing. He is credited for pioneering work in various areas of solidification processing: molten metal processing and filtration of metals; aluminum foundry engineering; plasma deposition; and spray casting/forming. Professor Apelian has more than 400 publications to his credit and four books, which he has co-edited. He has served on, and chaired, several national materials advisory boards for the National Research Council. Professor Apelian has been an active member of TMS for more than 30 years.

Pictures from conference

Papers presented:

Optimization of Gas Carburizing Process in Batch Furnaces with Endothermic Carburizing Atmosphere

Authors:

Olga Karabelchtchikova,Md. Maniruzzaman, Richard D. Sisson, Jr.

The paper addresses the current industrial issues with the gas carburizing process control and carburizing time/cost optimization. The optimization strategy is based on 1) understanding the effect of process parameters on the mass transfer coefficient and carbon diffusivity in austenite; 2) functional correlation of the observed variations in the process parameters on the kinetics of carburizing; and 3) developing a robust optimization technique to achieve the desired case depth with minimum cost and processing time. The index of performance for the process optimization involves both the surface carbon concentration and the case depth. While the first parameter depends on accurate control of the atmosphere and the carbon potential in the furnace, the case depth is primarily influenced by the temperature in the furnace and the duration of the carburizing process. Application of this optimization technique will result in significant energy reduction by shortening cycle time and thereby enhanced furnace capacity.

Powder Metallurgy: The Challenges of a Rapidly Changing Global Industry

Authors:

Chickery Kasouf

Powder metallurgy (P/M) produces components for many OEM and higher tier suppliers. As manufacturing growth shifts away from the United States into other economies, especially Asia, North American companies are faced with significant challenges. For example, GKN, the world's largest producer of P/M parts, recently closed four US plants as part of a consolidation in response to the contraction of the US automotive industry. On the other hand, there is tremendous growth in China resulting in many start-ups. Moreover, despite the inhospitable U.S. market, and the requirement for global capabilities, there is still start-up activity in the U.S. due to the low entry barriers in the industry. The challenges for P/M will be discussed in light of the implications for other metal processing industries.

Study fo the Effects of Heating Rate on 7000 Series Aluminum Alloys

Authors:

Courtney Nowill, Mohammed Maniruzzaman, Satya Shivkumar, Richard Sisson

Abstract

The quench sensitivity of various alloys has been studied with the use of the Jominy end quench test. Some studies have shown that heating rates also have an effect on mechanical properties, but data is scarce in the literature. A methodology has been developed in order to study the effects of heating rates. The apparatus designed is for a type of "reverse" Jominy test and results in one dimensional heating throughout the specimen, and therefore, a distribution of heating rates. Two 7000 series alloys, AA7075 and AA7136, were heated using this method to study the effects of heating rate on both solution and aging heat treatments. The effects of a rapid heat up by immersion in a salt bath were also studied versus the effects of a slow air furnace heat up. This study provides a better understanding of the effects of heating rate on 7000 series aluminum alloys.

Specific Heat and Thermal Conductivity Measurements Parallel and Perpendicular to the Long Axis of Cobalt Nanowires

Authors:

N. R. Pradhan, H. Duan, J. Liang, G. S. Iannacchione

Abstract

This paper reports the synthesis and sample construction as well as measurements of the specific heat and thermal conductivity of cobalt nanowires (CoNWs). Specific heat (cp) and thermal conductivity (k) is measured by an AC calorimetric technique from 300 to 400 K parallel and perpendicular to the CoNW long-axis. The specific heat both parallel (C iip ) and perpendicular (Cip ) to the long-axis deviates strongly from the bulk amorphous powder behavior above room temperature. The perpendicular thermal conductivity (Ki ) of CoNWs follows a bulk-like behavior revealing a maximum value near 365 K, indicating the onset of boundary-phonon scattering. The parallel thermal conductivity (Kii ) increases smoothly with the increase of temperature from 300 to 380 K and appears to be dominated by phonon-phonon scattering.

Thermo-Mechanical Analysis of Continuous Casting with Reduction by Using Meshless Methods

Authors:

L. Zhang, Y. Rong

Abstract

Meshless method can solve large deformation problem without re-meshing. An integrated analysis model of heat transfer and thermal stress based on meshless methods has been developed for continuous casting with mechanical reduction. The Finite Point Method is employed to build a thermal module with the solutions of the non-linear material properties and heat latent. The stress-strain analysis module is established based on the meshless Local Petrov-Galerkin method. The large deformation stress-strain is presented by Green-Lagrange formulation. Finally, the model is applied in the simulation of continuous casting with reduction. Temperature distribution in the slab was calculated. Thermal stress evolution in the mechanical reduction regions is evaluated. Successful solution of large deformation problem shows the potential benefits of meshless methods to continuous casting simulation.

Heat Transfer Coefficient Study for Quenching by Experiment and CFD Modeling

Authors:

G. Wang, L. Zhang, B. Xiao, Y. Rong, R. Sisson, Jr.

Abstract

Heat transfer coefficient is a key issue in quenching process, and the HTC values obtained from experiments are limited to evaluate/predict the quenching ability of real production due to the complicated flow and workpiece geometry. In this paper, CFD method is employed to instruct the design and to amend the results of the experiments where several important factors will be considered including air velocity, air temperature, and humidity. Based on the heat balance equation the variable HTC is calculated and will be applied in real quenching.

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