The process of room temperature rolling is a straightforward and efficient method for producing high strength Mg-Li alloys, but the underlying strengthening mechanism remains unclear. In this study, we successfully enhanced the tensile properties of a novel dual-phase Mg-Li alloy through room temperature rolling, with a remarkable yield strength of 201 MPa and an elongation-to-failure of 14 %. Microhardness testing was conducted to evaluate the contribution of the Mg- and Li- phases to the improvement in strength. The results demonstrate that the hardness of Mg-phase reaches 60 HV, which is significantly higher than the 49 HV observed in Li-phase, indicating that the Mg-phase after rolling plays a pivotal role in enhancing material strength. The presence of a high density of dislocations stored in the Mg-phase emerges as the dominant factor contributing to improved strength in Mg-Li alloys. In-situ compression testing reveals that 〈c + a〉 slip activation and twinning-induced slip serve as internal mechanisms for continuous deformation and hardening within the Mg-phase. Despite numerous precipitated Mg-phase particles within the Li-phase matrix, the hardness analysis reveals minimal strain-induced phase transformation effects on the overall strength of the Al-free and Zn-free Mg-Li alloy. These findings provide valuable insights for designing and fabricating high-strength dual-phase Mg-Li alloys.

中文翻译：

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室温轧制过程中以连续硬化 Mg 相为主的 Mg-Li 合金的强化


室温轧制工艺是生产高强度 Mg-Li 合金的一种简单而有效的方法，但潜在的强化机制仍不清楚。在本研究中，我们成功地通过室温轧制增强了一种新型双相 Mg-Li 合金的拉伸性能，其屈服强度达到 201 MPa，断裂伸长率为 14%。进行显微硬度测试以评估 Mg 和 Li- 相对强度提高的贡献。结果表明，Mg相的硬度达到60 HV，明显高于Li相观察到的49 HV，表明轧制后的Mg相在提高材料强度方面起着关键作用。存储在 Mg 相中的高密度位错的存在成为有助于提高 Mg-Li 合金强度的主要因素。原位压缩测试表明，〈c + a〉 滑移激活和孪晶诱导滑移是 Mg 相内连续变形和硬化的内部机制。尽管 Li-phase 基体中有许多沉淀的 Mg-phase 颗粒，但硬度分析显示，应变诱导的相变对无铝和无锌 Mg-Li 合金的整体强度的影响最小。这些发现为设计和制造高强度双相 Mg-Li 合金提供了有价值的见解。