= Solution
At a common test <temperature> and otherwise comparable microstructure, chemical order generally raises the <yield strength>. An ordinary FCC <dislocation> displaced by $a\langle110\rangle/2$ can interchange Au and Cu sublattices, creating an <antiphase boundary> behind it. This additional energy resists slip; paired <dislocations> can restore the order after the second member passes. The disordered phase does not pay the same ordering penalty. Comparing specimens actually tested at their different phase-stability temperatures also includes temperature-dependent mobility and recovery, so the ordering argument alone does not predict a unique measured strength ratio.
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