This work is focused on the analysis of the high-density infrared (HDI) sheet fabrication process of powder compacts. Measurements of material properties and distribution of incident heat flux on processed powder sheet surfaces have been conducted with the aim of obtaining a complete set of data that can be used as input in computer simulation software. It was found that these materials exhibit significant anisotropy in thermal conductivity. Indirect measurements indicate that there are small variations in density across the thickness of the powder compacts. Temperature data were obtained from thermocouples placed on the backside of the sheet. The evolution of thermal profile during a static pulse was investigated by using a three-dimensional finite volume model. Numerical simulation results are very sensitive to the surface emissivity. Numerical simulation results agree very well with experimental results for the case in which no liquid pool was formed during HDI processing.

Oak Ridge National Laboratory has developed a unique rapid heating capability utilising a high density infrared (HDI) radiant plasma arc lamp. Power densities f3 . 5 W cm 22 are achievable over an area 3563 . 175 cm. The power output of the lamp is continuously variable over a range from 1 . 5% to 100% of available power, and power changes can occur in v20 ms. Processing temperatures f3000uC can be obtained in a wide variety of processing environments, making HDI a flexible processing tool. Recently, this newly developed heating method was used to investigate selective softening, i.e. hardness reduction of 6063-T6 aluminium alloy. By changing the incident power and exposure time, the percentage reduction in hardness and softened zone size can be varied. It is shown that computer modelling can be used to predict the thermal history and the resulting heat affected zone during HDI processing. In the present work, a 50% reduction in hardness was achieved and confirmed by mechanical testing and microstructural investigation. Micrographs of softened aluminium show that Mg 2 Si precipitates had dissolved back into solution. This new approach allows materials to be engineered for a predetermined response to dynamic loading or other environmental situations. SE/S282

New corrosion-resistant, iron-based amorphous metals have been identified from published data or developed through combinatorial synthesis, and tested to determine their relative corrosion resistance. Many of these materials can be applied as coatings with advanced thermal spray technology. Two compositions have corrosion resistance superior to wrought nickel-based Alloy C-22 (UNS # N06022) in some very aggressive environments, including concentrated calcium-chloride brines at elevated temperature. One of these compositions, SAM1651, is discussed in detail to illustrate the promise of this general class of materials.

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