The fundamentals of mechanochemical processing

It has been demonstrated that the activation of chemical reactions by mechanical energy can lead to many interesting applications, ranging from waste processing to the production of advanced materials with novel microstructures and enhanced mechanical properties. In this article, the status of three types of mechanochemical processing is reviewed—mechanical milling, mechanical alloying, and reaction milling. For more information, contact P.G. McCormick, University of Western Australia, Nedlands; WA 6907 Australia, telephone 61893803122; fax 618938801116; e-mail pgm@mech.uwa.edu.au     

Fabricating sports equipment components via powder metallurgy

Powder metallurgy (P/M) offers a viable, cost-effective approach to fabricating sports and leisure equipment components. Both complex, monolithic parts and parts produced from materials of quite different densities can be manufactured by this technique. In the latter category, lightweight titanium and heavyweight tungsten can be used in combination to optimally distribute mass, such as in golf club heads. Examples of P/M components used in golfing, skating, baseball, and even darts are presented. For more information, contact F.H. Fores, University of Idaho, Institute for Materials and Advanced Processes, Mines Building Room 321, Moscow, Idaho, 83844-3026; telephone (208) 885-7989; fax (208) 885-4009; e-mail imap@uidaho.edu.     

Control of microstructure and component shape in rapidly solidified/powder metallurgy titanium alloys

Extensive use of titanium rapidly solidified/powder metallurgy (RS/PM) components requires not only careful control of the microstructure for optimum mechanical properties but also cost-effective processing. A new direct reduction process for production of titanium alloy powder will be presented. Control of the microstructure in conventional alloys such as Ti-6Al-4V and in non-conventional dispersion strengthened terminal and intermetallic alloys will be discussed. It will be shown that RS/PM processing allows production of a fine grain size and useful dispersions of rare earth and metalloid phases; phases which normally form as gross undesirable particles. The use of hydrogen as a temporary alloying element, thermochemical processing, will be discussed and it will be demonstrated how this treatment can lead to refined microstructures with enhanced mechanical behaviour. Cost-effective processing using near-net shape techniques such as the ceramic mold process, rapid omnidirectional compaction (ROC), and the use of RS/PM preforms for subsequent isothermal forging will be presented. Microstructural control and shape-making used in unison should lead to increased use of titanium components in advanced aerospace systems. work done as a consultant to Metcut-Materials Research Group