Abstract
Oak Ridge National Laboratory has developed a unique rapid heating capability utilising a high density infrared (HDI) radiant plasma arc lamp. Power densities ≤3≤5 W cm-2 are achievable over an area 35 × 3·175 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 <20 ms. Processing temperatures ≤3000°C 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 Mg2Si 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.
Original language | English |
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Pages (from-to) | 220-228 |
Number of pages | 9 |
Journal | Surface Engineering |
Volume | 20 |
Issue number | 3 |
DOIs | |
State | Published - Jun 2004 |
Keywords
- Aluminium alloys
- Effective processing time
- High density infrared processing
- Plasma arc lamp heating
- Preferential heat treating
- Radiant heat transfer modelling
- Thermophysical properties