Rapid Solidification Processing: Melt Spinning of Al-High Si Alloys

Rapid solidification processing is a technique used for refining the primary silicon and seems to be the most promising technique for the production of high Si Al-Si alloys (i.e. Si content greater than 17 wt.%). There are number of routes which can be used to produce rapid solidification, including spray methods, weld methods, and chill methods. Of these, melt spinning is the most widely used industrially due to its high cooling rate and the ability to process large volumes of materials. This paper summarizes melt spinning and rapid solidification, highlighting a potential production route for aluminium-high silicon alloys involving melt spinning followed by hot isostatic processing.

A Preliminary Study of the Development of 9Cr Fe-Base ODS Alloys: The Effects of Minor Elements and Cooling Rate

Three 9Cr Fe-base ODS alloys were prepared by MA (mechanical alloying) and HIP (hot isostatic processing) processes. The addition of Ti was confirmed to have a significant effect on the tensile properties at high temperature as well as at room temperature, while the V addition did not clearly show its effect on the microstructure or on the mechanical porperties at both temperatures. Fine and evenly distributed Y and Ti containing complex oxide was detected in the Ti added ODS alloy. They were attributed to the good high temperature strengths. Different cooling rates from the normalizing temperature did not result in a significant change in the grain boundary characters, but rather significant differences were observed in the mechanical properties. This is mainly attributed to the difference of the matrix phase rather than to the grain size distribution or the grain boundary characters.

Hot Isostatic Processing

Hot isostatic pressing (HIP) is a process refinement available to address internal porosity in castings. The HIP process may be used, in particular, for applications requiring very high quality and performance. This chapter discusses the principles, advantages, and disadvantages of HIP. It describes the effect of HIP on tensile properties and on the fatigue performance of aluminum alloy castings. In addition, the chapter discusses the processes involved in radiographic inspection of HIP-processed castings.