Mg-2.5Nd-0.5Zn-1Zr合金的力学性能研究

Study on Mechanical Properties of Mg-2.5Nd-0.5Zn-1Zr Alloy

通过数值模拟、X光无损检测和拉伸试验对Mg-2.5Nd-0.5Zn-1Zr合金的室温力学性能进行了研究。结果表明：Mg-2.5Nd-0.5Zn-1Zr合金属于缺口敏感性材料,单铸拉棒的表层对其力学性能有明显的影响,未加工的单铸拉棒抗拉强度、屈服强度和伸长率分别为233.1 MPa、162.8 MPa和3.5%,且离散性大。将其从准12 mm加工到准10 mm后,抗拉强度、屈服强度和伸长率达到257.3 MPa、180.8 MPa和4.6%,力学性能有明显提升,且数据更加稳定。Mg-2.5Nd-0.5Zn-1Zr合金制备的四种试样,均达到了设计指定的力学性能指标。其中加工后的单铸拉棒强度最好,抗拉强度和屈服强度分别超出设计要求11.9%和27.3%,附铸试样的强度和加工后的单铸试样相当。本体剖切试样的伸长率最高,其抗拉强度、屈服强度和伸长率分别为225.9 MPa、153.3 MPa和6.1%,分别超出了设计要求13%、27.8%和52.5%。四种试样中,24 mm壁厚的单铸试板的强度和铸件本体强度最为接近,单铸拉棒和附铸试样的强度分别为铸件本体强度的113.9%和112.5%。

The mechanical properties at room temperature of Mg-2.5 Nd-0.5 Zn-1 Zr alloy were investigated by numerical simulation, X-ray non destruction and tensile test. The results show Mg-2.5 Nd-0.5 Zn-1 Zr alloy shows high notch sensitivity,and the surface of single cast pull rods has significant influences on the mechanical properties. Those unprocessed single cast pull rods perform the tensile strength of 233.1 MPa, yield strength of 162.8 MPa and elongation of 3.5%, and their tests data are discrete. After machined from 准12 mm to 准10 mm, the tensile strength, yield strength and elongation are 257.3 MPa,180.8 MPa and 4.6%, respectivle. The mechanical properties improve obviously, and the test data become stable. The properties of four kinds of specimens prepared with Mg-2.5 Nd-0.5 Zn-1 Zr alloy meet the designed mechanical properties requirements.After maching, single cast pull rods perform the best strength, its tensile strength and yield strength are higher than the designed requirements by 11.9% and 27.3%, respectively. The strengths of cast-on specimen and single cast pull rods after maching are almost the same. The best elongation test results can be gained from excised bars, the tensile strength, yield strength and elongation are 225.9 MPa, 153.3 MPa and 6.1%, respectively, which are higher than designed requirements by13%, 27.8% and 52.5% respectively. As for the four kinds of specimens, the strengths of single cast pull rods with the thickness of 24 mm and excised bar are the nearest. The strength of single cast pull rods and cast-on specimen is 113.9% and112.5% of that of excised bars, respectively.