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Control of Microstructure in a Spraycast Al-Mg-Li-Zr Alloy
| Content Provider | Semantic Scholar |
|---|---|
| Author | Hogg, Simon C. Palmer, Ian Graham Grant, Patrick S. |
| Copyright Year | 2004 |
| Abstract | Abstract This paper describes the microstructural investigation of an Al-5.31Mg-1.15Li-0.28Zr alloy produced by spraycasting. Following a dispersoid precipitation treatment of 4h at 400°C, cylindrical samples were hot compressed to a range of total strains and a range of strain rates at temperatures between 250-400°C. Electron backscattered diffraction showed a strong dependence of grain size on compression temperature with new grains nucleating at regions of microscopic strain localisation such as triple points and grain boundaries. There was an inverse relationship between the size of these new grains and the Zener-Holloman factor during compression. The microstructures from the small scale compression experiments have been compared with those of larger scale forgings, and indicated that under similar conditions, microstructural evolution was broadly similar. 1. Introduction Al-Mg-Li alloys offer the potential to reduce weight and improve performance in structural aerospace applications and alloys developed using conventional casting routes have provided excellent properties [1]. Critical to the alloy performance is the use of sometimes complex heat treatments that may result in quench cracking/distortion. Non-heat-treatable mechanically alloyed (MA) materials offering similar or enhanced properties have also been developed [2], but only in small quantities. The sub-micron grain sizes typical of MA materials may also have deleterious effects on the alloy fatigue crack growth rates because of reduced crack closure effects, and thermal stability during hot working. Spraycast Al-Mg-Li alloys offer the potential for microstructural refinement, extended alloying capability and reduced levels of embrittling elements associated with Li (Na, K and H) [3]. As part of a wider study to develop a spraycast non-heat-treatable Al-Mg-Li alloy of intermediate 1-5µm grain size, this paper presents an investigation of the microstructure of a spraycast Al-Mg-Li-Zr alloy and its microstructural evolution during post-spray hot compression as a function of temperature, strain, and strain rate. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://www.icaa-conference.net/ICAA9/data/papers/GP%2035.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
