Elastic Effects on Phase Segregation in Alloys with External Stresses

We investigate, via computer simulations, coherent phase segregation in a microscopic model alloy consisting of $A$ and $B$ atoms of unequal sizes on a square lattice. The effective Hamiltonian, obtained by minimization over the displacement of the atoms from their lattice positions, contains long range linear elastic interactions that cause the precipitates to be highly anisotropic. Under external load they acquire "wavy" long sides and align parallel to one of the axes. Their size, measured by the reciprocal of the number of $A-B$ bonds, grows approximatively as $t^{\frac{1}{3}}$.