The microstructure evolution, mechanical property and deformation mechanism of rolled Al3La/Mg–Li–Al–Zn composites prepared by in-situ synthesis

Based on the in-situ synthesis process, this study proposes a novel process that introduces lithium salt-modified La2O3p as a precursor into Mg–Li–Al–Zn (LAZ) alloy melt, achieving the controllable preparation of in-situ synthesis Al3La/LAZ composite. The as-cast composite was processed into plate by extruded and subsequently rolled at 300 °C. The primary focus of this study was on the microstructure evolution, mechanical mechanism, and deformation behaviour of the rolled composite. The findings suggested that lithium salt-modified La2O3p underwent a series of reactions in LAZ alloy fusant, leading to the in-situ precipitation of Al3La phase, refining microstructure and enhancement of the overall strengths of the composite. The strengthening analysis result confirmed that precipitation strengthening and dislocation strengthening are the major contributions. In addition, the microstructure change during deformation was elucidated using EBSD technique. The results revealed that the intragranular slip in the composite changed from primarily prismatic slip to a combination of prismatic and pyramidal slips during tensile deformation. The activation of extension twins did not fully comply with the Schmidt factor (SF) law, with approximately 75 % of the 127 analyzed extension twins following the SF law, during compression deformation.