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Effect of pressure on order and stability in alloys: The case of Al-Ge

Conference ·
OSTI ID:6491195
;  [1];  [2]
  1. Lawrence Livermore National Lab., CA (United States)
  2. Oak Ridge National Lab., TN (United States)

A parameter-free approach to phase stability in substitutional alloys is applied to the influence of pressure on order-disorder phenomena in Al-Ge. The methodology is based upon an application of the Generalized Perturbation Method to the Korringa-Kohn-Rostoker scattering formulation of the Coherent Potential Approximation. For fcc-based Al-Ge alloys, it is shown that the tendency towards phase separation at normal pressure originates from a structural difference between the pure species. By applying pressure, the structural energy difference is reduced, and a significant increase in the tendency towards order, especially for Al-rich alloys, is theoretically observed, leading, as an example, to the possible observation of a DO[sub 22] ordered state around 25 at. %. The electronic origin of the ordering tendencies induced by pressure is discussed and the theoretical predictions are related to experimental facts.

Research Organization:
Lawrence Livermore National Lab., CA (United States)
Sponsoring Organization:
DOE; USDOE, Washington, DC (United States)
DOE Contract Number:
W-7405-ENG-48; AC05-84OR21400
OSTI ID:
6491195
Report Number(s):
UCRL-JC-110687; CONF-921101--115; ON: DE93013842
Country of Publication:
United States
Language:
English