Understanding the mechanism of martensitic transformation is of great importance in developing advanced high strength steels, especially TRansformation-Induced Plasticity (TRIP) steels. The TRIP effect leads to enhanced work-hardening rate, postponed onset of necking and excellent formability. In-situ transmission electron microscopy has been performed to systematically investigate the dynamic interactions between dislocations and  martensite at microscale. Local stress concentrations, e.g. from notches or dislocation pile-ups, render free edges and grain boundaries favorable nucleation sites for  martensite. Its growth leads to partial dislocation emission on two independent slip planes from the hetero-interface when the austenite matrix is initially free of dislocations. The kinematic analysis reveals that activating slip systems on two independent {111} planes of austenite are necessary in accommodating the interfacial mismatch strain. Full dislocation emission is generally observed inside of austenite regions that contain high density of dislocations. In both situations, phase boundary propagation generates large amounts of dislocations entering into the matrix, which renders the total deformation compatible and provide substantial strain hardening of the host phase. These moving dislocation sources enable plastic relaxation and prevent local damage accumulation by intense slipping on the softer side of the interfacial region. Thus, finely dispersed martensite distribution renders plastic deformation more uniform throughout the austenitic matrix, which explains the exceptional combination of strength and ductility of TRIP steels.

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FeS2‐sensitized ZnO@ZnS nanorod arrays are fabricated by a two‐step solution immersion and a subsequent sulfurization. The material properties including structure, morphology, and photoluminescence are investigated by a variety of characterization methods. As compared with ZnO@ZnS core/shell structure, FeS2‐sensitized ZnO@ZnS nanorod arrays show improved optical absorption property with the extension of the absorption edge into the range of visible light. The photoresponse performance of FeS2‐sensitized Zno@ZnS is also enhanced as the photocurrent density at 1.0 V is dozens of times larger than that of ZnO@ZnS nanorods. The cause for the difference in such material properties of these two materials is discussed. In this work, a new method for sensitizing wide bandgap ZnO@ZnS nanorod arrays with improved light response performance is presented.

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