Revealing the microstructure, texture evolution mechanism and mechanical properties of cryogenic rolled and microtherm aged AA6061

In this paper, 6061 Al alloy was rolled under room temperature and cryogenic conditions, respectively. The changes in mechanical properties and microstructure of 6061 Al alloy under different rolling processes were investigated, and the influential mechanism of temperature on texture and dislocation distribution during the rolling process was analyzed. Microstructure characterization indicated that compared to room temperature rolling, the dynamic recovery was significantly suppressed under cryogenic rolling process, which led to a more discrete distribution and higher density of dislocations within the material. Additionally, cryogenic rolling also influenced the texture evolution, increasing the proportion of R-Cube texture during the initial deformation stage, limiting texture transformation along the α-fiber and γ-fiber, and at the same time, promoting a transformation along the β-fiber to Brass texture. Mechanical results revealed that the sample subjected to medium cryogenic rolling and microtherm-aging obtained an excellent mechanical property with a yield strength (YS) of 320.8 MPa, an ultimate tensile strength (UTS) of 359.7 MPa, and an elongation (EL) of 15 %. The high strength was mainly attributed to the more dispersed dislocation and their high density as well as the aging strengthening, while the high ductility resulted from the Cube texture and aging induced boundaries with misorientation angles between 0° and 15°.