Conventional ultrafine-grains can generate high strength in Mg alloys, but significant tradeoff of corrosion resistance due to inclusion of a large number of non-equilibrium grain boundaries. Herein, an ultrafine-grain structure consisting of dense ultrafine twins is prepared, yielding a high strength up to 469 MPa and decreasing the corrosion rate by one order of magnitude. Generally, the formation of dense ultrafine twins in Mg alloys is rather difficult, but a carefully designed multi-directional compression treatment effectively stimulates twinning nucleation within twins and refines grain size down to 300 nm after 12-passes compressions. Grain-refinement by low-energy twins not only circumvents the detrimental effects of non-equilibrium grain boundaries on corrosion resistance, but also alters both the morphology and distribution of precipitates. Consequently, micro-galvanic corrosion tendency decreases, and severe localized corrosion is suppressed completely. This technique has a high commercial viability as it can be readily implemented in industrial production.

传统的超细晶粒可以在镁合金中产生高强度，但由于包含大量非平衡晶界，因此在耐腐蚀性方面有显着的权衡。在此，制备了由致密超细孪晶组成的超细晶粒结构，强度高达 469 MPa，腐蚀速率降低一个数量级。通常，在镁合金中形成致密的超细孪晶是相当困难的，但精心设计的多向压缩处理有效地刺激了孪晶内的孪晶形核，并在 12 道次压缩后将晶粒尺寸细化到 300 nm。低能孪晶的晶粒细化不仅避免了非平衡晶界对耐蚀性的不利影响，但也会改变沉淀物的形态和分布。因此，微电偶腐蚀倾向降低，严重的局部腐蚀被完全抑制。该技术具有很高的商业可行性，因为它可以很容易地在工业生产中实施。