单道次热轧制备具有双峰晶粒结构的高性能AZ31镁合金

Preparation of High-Performance AZ31 Magnesium Alloy with Bimodal Grain Structure by Single-Pass Hot Rolling

摘要:

以AZ31镁合金为研究对象，利用单道次热轧制造出具有双峰晶粒结构的镁合金，并探讨该结构如何提高合金的强度和塑性。结果表明，在350~450 ℃的轧制温度下，尤其是在大变形（≥40%）条件下，双峰晶粒结构的形成更为明显。双峰晶粒结构的优化比例和分布在同时提高合金的强度和延展性方面起着关键作用。在轧制变形量为40%、轧制速度75 m/min和轧制温度400 ℃的条件下制备出的轧制板材具有双峰晶粒结构，达到了258.3 MPa的抗拉伸强度和17.1%的延伸率。因此，调整轧制参数，包括温度、变形量和轧制速度，对于优化双峰晶粒结构至关重要，从而实现改善塑性和保持高强度之间的平衡。

Abstract:

AZ31 magnesium alloy was used as the object of study to fabricate an alloy with the bimodal grain structure using single-pass hot rolling, and to explore how this structure enhances the strength and plasticity of the alloy. The results show that the formation of the bimodal grain structure is more pronounced at rolling temperatures ranging from 350 °C to 450 °C, especially under conditions of large reduction (≥40%). The optimized proportion and distribution of the bimodal grain structure play a pivotal role in simultaneously enhancing the strength and ductility of the alloy, significantly impacting the mechanical properties. The rolled sheet with the bimodal grain structure achieves an ultimate tensile strength of 258.3 MPa and an elongation of 17.1% under a rolling reduction of 40% with the rolling rate of 75 m/min and rolling temperature of 400 °C. Adjusting rolling parameters, including temperature, reduction ratio and rolling rate, is crucial for optimizing the bimodal grain structure, thereby achieving a balance between plasticity improvement and high strength maintenance.