高塑性Mg-Al-RE合金稀土相演化与塑性变形机理研究

Magnesium alloys have hexagonal close packing crystal structure, poor plasticity is the most important reason to limit its popularization and application. This work will improve the mechanical properties and plastic deformation ability of Mg-Al alloy intends to use rare earth elements alloying, such as cerium, neodymium , the evolution of rare earth phase (such as Mg41Nd5 Mg24Y5, Mg12Ce etc) and its influence on plastic deformation mechanism will be study, the rare earth elements influence of solid solution and metallographic will be calculated combined with the first principles . Evolution mechanism of alloy phase will be researched with the changing of the rare earth content using universal testing machine, OM, XRD, SEM, TEM and other analysis methods; the evolution mechanism of different status of rare earth alloy phase structure, morphology and distribution will be studied, the influence of rare earth phase to plastic deformation such as sliding, twins and dynamic recrystallization will be studied . The relationship between high plastic magnesium alloy "composition - rare earths phase - performance "will be revealed, the ability of plastic deformation of magnesium alloy will be improved , solve basic theory problem of enlarge the formablity of magnesium alloy.

镁合金具有密排六方晶体结构，塑性差是限制其推广应用的重要原因。本项目拟利用钕、铈等稀土元素合金化来提高Mg-Al系镁合金的力学性能和塑性变形能力，研究稀土相（如Mg41Nd5,Mg24Y5, Mg12Ce等）的演化及其对塑性变形机理的影响,结合第一性原理分析计算稀土元素对固溶体和合金相的影响。利用电子万能试验机、OM、XRD、SEM、TEM等分析测试手段，研究合金相随稀土添加量的变化规律；研究不同状态合金中稀土相结构、形态、分布的演化机理，研究稀土相对合金滑移、孪生、动态再结晶等塑性变形的影响。揭示高塑性稀土镁合金的"成分-稀土相-性能"之间的关系，提高镁合金塑性变形性能，解决提高镁合金塑性成形性能的基础理论问题。

镁合金具有高的比强度和比刚度，良好的电磁屏蔽和阻尼性等优点，在交通运输、航空航天等领域有着广泛的应用前景，但塑性差限制了其推广应用。本项目通过理论计算了AlY等合金相的结构及力学性能，通过实验研究了Ca、Sb对镁稀土合金的影响，分析了合金相在塑性变形过程中的作用，得到了一些合金相的基础数据和合金元素对镁合金的影响能力数据，优化后的合金室温延伸率达到了25.5%，提高了镁合金的塑性变形能力。通过这些研究，丰富了镁合金基础理论数据，为镁合金更广泛的应用打下了基础。