LAUSR

The existence of short-range order (SRO) has a significant impact on the mechanical properties in metallic alloys [1-3], where the deformation behaviors of the alloys can be directly correlated to the degree of SRO [4-6]. Recently, we have shown that the SRO domain structures can be directly imaged via Energy-filtered Transmission Electron Microscopy (EFTEM), in both Ti-Al alloys and CrCoNi medium entropy alloys [7, 8]. With the presence of an SRO domain cluster, one of the hypothesized mechanisms to explain the SRO-induced strengthening is based on the potent interaction between SRO domain clusters and gliding dislocations, where leading dislocations need to overcome the energy barrier of creating “diffuse” antiphase boundaries (DAPB) to slip[9, 10]. A diffuse residual strain field would raise from the creation of DAPBs, altering following dislocation motions and local stacking fault energy. Direct measurement of the local strain of the DAPB is, therefore, of great interest for understanding the atomic origin of SRO strengthening and its relation to deformation behavior such as dislocation motion and deformation twinning.