On the Texture Weakening During Electropulse Annealing Treatment of Mg-1Ce Alloy: The Role of Nucleation and Nucleus Gro
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CO2 emissions from the transport sector are one of the most urgent climate problems that can be tackled by reducing vehicle mass through the use of cost-effective, lightweight structural components made from wrought magnesium (Mg) alloys.[1–3] However, poor room temperature formability significantly increases the fabrication cost and lowers the efficiency, which has largely limited the commercial application of wrought magnesium alloys so far.[4] The fundamental cause of magnesium’s poor formability at ambient temperatures lies in its hexagonal close-packed (HCP) crystal structure (c/a = 1.624), which favors the activation of basal hai slip and 10 12 10 11 extension twinning (ETW) over other JIE KUANG, GANG LIU, and JUN SUN are with the State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049, P.R. China. Contact e-mail: [email protected]; [email protected] XINPENG DU is with the The College of Optics & Photonics, University of Central Florida, Orlando, FL 32826 TALAL AL-SAMMAN is with the Institut fu¨r Metallkunde und Materialphysik, RWTH Aachen University, 52056 Aachen, Germany. XIAOHUI LI is with the School of Mechatronics Engineering, Foshan University, Foshan 528000, P.R. China. Contact e-mail: [email protected] Manuscript submitted April 2, 2020; Accessed September 6, 2020.
METALLURGICAL AND MATERIALS TRANSACTIONS A
deformation modes. The combination of these deformation mechanisms often leads to the development of a strong basal texture during the rolling of Mg. This type of texture, together with the lack of easily activated deformation modes out of the basal plane, contributes to catastrophic failure in subsequent processing, especially when the process is associated with sheet thinning. Therefore, introducing weak and non-basal textures in Mg sheets is the key to improving the formability and reducing mechanical anisotropy.[4,5] Since the deformation texture is determined by the selection of operating slip/twinning systems and their corresponding shear amount, one possible way to modify the texture is by designing sophisticated processing techniques with a variation of the stress state. Some of these techniques reported in the literature are single roller drive rolling(with one roll driven by the motor and the other rotating freely[6]), differential speed rolling,[7] high speed rolling,[8] equal channel angular extrusion (ECAE),[9,10] and pre-rolling along the transverse direction.[11] The drawback of these techniques is their rather complex setup in comparison to conventional processing, which has higher industrial scalability. Therefore, the studies on texture modification through recrystallization during/after conventional rolling are far more frequent compared to asymmetric rolling, for example.[12–20]
Mackenzie et al. first reported an abnormal extrusion texture in a RE (RE = rare earths)-added alloy, WE43. Instead of orienting the basal planes approximately parallel to the extrusion direction, the recrystallized grains in the alloy
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