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• The microstructure evolution of AXM050703 alloy was systematically studied. • The interaction of {10–12} twins, {10–11} - {10–12} twins and kinks were studied. • The multi-pass rolled samples with different microstructures were prepared. • The strength of these rolled alloy (alloying elements only 1.5 wt.%) is higher than AZ31B. The dynamic microstructure and texture of dilute Mg-0.50Al-0.71Ca-0.33Mn (wt.%) during hot rolling at two slab temperatures were investigated by electron backscattered diffraction (EBSD) and high resolution transmission electron microscopy (HRTEM). The results show that the development of the rolling microstructures is to first form {10–12} extension twins in the original grains, thereby forming the extension-twinned regions, and then to further form {10–11} - {10–12} double twins and kinks in the extension-twinned regions, and finally to form continuous dynamic recrystallized (continuous DRXed) grains in the double twins and the cross parts of the shear-deformed coarse extension-twinned regions. These extension twins, double twins and kinks show a decisive effect on the formation of rolling texture. The number of {10–11} - {10–12} double twins and resultant the continuous DRX process are strongly affected by the rolling slab temperature and the reduction thickness per pass. By optimizing the rolling conditions, texture and microstructures of the multi-pass rolled Mg-Al-Ca-Mn alloy sheets are successfully modified. Although the total alloy content is only 1.5 wt.%, these Mg-Al-Ca-Mn alloy sheets show much higher strength than the commercial Mg-3Al-1 Zn (wt.%) (AZ31B) sheet. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract Cold spray additive manufacturing (CSAM) provides a potential solid state manufacturing route to fabricate variety of aluminum matrix composites (AMCs) with reduced possibility of undesired chemical reactions and residual thermal stresses. This study presents a hybrid (i.e. hot compression + hot rolling) post-deposition treatment to reinvigorate the mechanical properties of cold spray additively manufactured Al/B 4 C composites. The as-deposited samples were initially subjected to 30% thickness reduction via hot compression treatment at ∼500 °C followed by a hot rolling treatment with 40% thickness reduction in 2 passes. Electron backscatter diffraction (EBSD) and high resolution transmission electron microscopy (HRTEM) results revealed that after hybrid post-deposition treatment (involving 70% accumulative thickness reduction), the aluminum grains in the matrix were extensively refined due to simultaneous operation of continuous dynamic recrystallization (CDRX) and geometric dynamic recrystallization (GDRX). Furthermore, interfacial defects were remarkably reduced while the nature of Al/Al and Al/B 4 C interfacial bonding was changed from sheer mechanical interlocking to metallurgical bonding which facilitated efficient transference of applied load to uniformly dispersed bimodal B 4 C particles. As a result, ultimate tensile strength (UTS) and elongation (EL) of the as-deposited sample were simultaneously improved from ∼37 to 185 MPa and ∼0.3% to 6.2%, respectively. [ABSTRACT FROM AUTHOR]