In this talk, we present concurrent atomistic-continuum computational analysis to quantify: (a) the local internal stress accumulation induced by the formation of a micrometer-level dislocation pileup at a buried incoherent material interface; and (b) its contribution to the subsequent atomic-level phase transformation (PTs), reverse PTs, and twinning. The main novelty of this work is a simultaneous accommodation of the microscale plastic flow and the atomic-scale structure changes ahead of the slip-interface intersection within one single model. Our major findings are: (i) the slip-interface reaction-induced local stress intensity linearly increases with the dislocation density in a nanoscale pileup containing only several dislocations, but will exponentially ‘upper bend’ to a very high level upon a further increase of the number of dislocations in a microscale pileup ; (ii) the PT always occurs ahead of the slip-interface intersection when the pre-sheared sample is subjected to a compression. The phases boundaries (PBs) and twin boundaries (TBs) in the resulting microstructure can be well picked up by the local stress/strain-based ‘Eshelby-type’ driving force; (iii) the product phase eventually grows into a wedge shape but transforms back (i.e., reverse PTs) to the parent phases. Twinning is then observed, for the first time, in between the parent phase and the product phase resulting from the reverse PTs; and (iv) quantitatively, the pileup-induced local stress is found to have caused a 60% reduction of the compression required for activating the PT. This work is a first characterization of the dynamics of PTs/twinning resulting from the reaction between a microscale dislocation slip and an atomically resolved interface. The gained knowledge will advance our understanding on how the multi-phase material behaves in a variety of complex physical processes.