The presence of nano-sized coherent precipitates is well known to have crucial impact on the mechanical behaviors of a broad class of shape memory alloys. The local stress gradient at the matrix-precipitate interface is predicted as induced by inter-lattice atomic disregistry. Due to the presence of the local disturbance fields, the preference for activating different martensitic variants, given the uni-directionality thereof, is influenced substantially. The resultant constitutive attributes are thus observed to undergo adjustments in terms of reduced transformation stress, strain and hysteresis in general agreement with experimental literature.