Achievement of exceptional strength-plasticity synergy for low-alloyed Mg–2Y alloy prepared by combining controlled diffusion solidification with rolling

The quality of wrought magnesium (Mg) alloys is closely linked to the quality of the cast ingots. Conventionally casting (CC) Mg–2Y ingots exhibit relatively coarse grain sizes. When CC ingots undergo rolling processing (CC-10-R), the resulting Mg–2Y sheets retain coarse grain sizes (∼11.87 μm), while precipitating a small number of Mg₂₄Y₅ nanoparticles (∼0.26%), as well as forming a strong C-type texture (∼10.91). The implementation of controlled diffusion solidification (CDS) effectively refines the grain size of Mg–2Y ingots and increases the content of Mg₂₄Y₅ particles. When CDS is combined with rolling (CDS-10-R), the grain size is refined to ∼5.57 μm, the precipitation of Mg₂₄Y₅ nanoparticles is increased to ∼1.79%, and the C-type texture was weakened to ∼7.74. The CDS-10-R shows an increase in strength of ∼51.8% and an enhancement in plasticity of ∼32.6% compared to CC-10-R. The enhancement in strength is primarily due to fine-grain strengthening (∼42.1% contributions) and precipitating strengthening (∼39.6% contributions). The improvement in plasticity is attributed to the weakening of the {0001} basal texture, which facilitates the activation of <c + a> slips. Compared to other wrought Mg–Y alloys, Mg–2Y sheets produced by combining CDS with rolling possess exceptional strength-plasticity combinations. This finding presents a novel route to achieving high strength and plasticity in low-alloyed rare-earth Mg alloys.