Localized microstructure enhancement via Friction Stir Processing for die cast components

Friction stir processing (FSP) is an outgrowth of Friction stir welding (FSW) that locally manipulatesthe microstructure by imparting a high level of energy in the solid state resulting in improved mechanicalproperties. This study has shown that FSP can be implemented as a post-casting method to locally eliminatecasting defects, such as porosity, which is generated by gas evolution during casting. Coarse second phases arebroken into fine nearly equiaxed particles and uniformly distributed in the matrix. Moreover, grain refinementis obtained by dynamic recrystallization during FSP. This results in improved microhardness, tensile propertiesand fatigue properties of the cast FSP processed A206 alloy. In addition, FSP is a viable means to producelocalized composite structures in cast Al components. Such improvements have important implicationsfor manufactured components for a variety of automotive and other industrial applications. The convenienceof FSP as a post-processing step that can easily be adapted during machining operation makes it veryattractive to adopt. These results will be reviewed and discussed

Opportunities and barriers to resource recovery and recycling from auto shredder residue - A CR3 communication

Worcester Polytechnic Institute (WPI), Colorado School of Mines (CSM), and the University of Leuven (KU Leuven) in Belgium have jointly established a collaborative research Center for Materials Resource Recovery and Recycling (CR3). TMS and CR3 have jointly established a strategic alliance, as the work of the center is well aligned with TMS's initiative in Materials and Society. Efforts are being made at CR3 to evaluate the economics of shredder residue recycling with the objective of providing specific strategic recommendations to the auto-shredder industry. Specifically the work CR3 involves examining certain aspects of commercializing shredder residue recycling. Some of these aspects include capital expenditure of an operational shredder residue recycling facility and operational capacity, modularity in construction, and operating costs of such a facility.status: publishe

Study of microporosity formation in nickel-base superalloys

peer reviewedThe susceptibility of nickel-base superalloys to microporosity formation is studied experimentally and theoretically. Analysis of a model introduced herein leads to formulation of a microporosity index, Ap*, which is expressed in terms of solidification parameters and alloy system properties. This index can be determined from information obtained by quantitative differential thermal analysis. The effect of composition on the formation of microporosity is evaluated. Thus, aluminum, titanium, and cobalt are found to increase, and chromium to decrease microporosity. The effect of carbon is beneficial or detrimental depending on the aluminum content in the alloy