DIFFUSION-INDUCED DISLOCATIONS IN RSP AL-MO

Samples of melt-spun alloys containing either 2. 2 at. % Mo or 0. 7 at. % Mo have been examined in the as-quenched state and after various annealing treatments. In the alloys containing 2. 2 at. % Mo, dislocation networks are produced and Al//1//2Mo precipitates are formed during annealing, whereas although Al//1//2Mo is precipitated in more dilute 0. 7 at. % Mo alloy, no change in dislocation density occurs. The dislocations in the 2. 2 at. % Mo samples separate regions of crystal which still contain the supersaturated solid solution from regions where the Mo has been removed from solution. Removal takes place only when the dislocations move by climb into the Mo-rich regions. These observations are discussed in terms of the generation of dislocations during diffusion with particular emphasis on the role of coherent and partially coherent interfaces.