Microstructure and mechanical properties of Mg-Zn-Gd-based alloys strengthened with quasicrystal and Laves phase

【摘要】 One kind of Mg3.5Zn0.6Gd-based alloy strengthened with quasicrystals was designed,and the effect of alloying elements on microstructure and mechanical properties of as-cast Mg-Zn-Gd alloy at room temperature and elevated temperatures were studied. The results indicate that MgZnCu Laves phase,which coexists with quasicrystal at grain boundary,emerges with the addition of copper element in Mg-Zn-Gd alloy. The strength of alloys exhibits the parabola curve with the increase of copper content. The alloy with 1.5%(mole fraction) Cu shows better mechanical properties at room temperature:tensile strength 176 MPa,yield strength 176 MPa and elongation 6.5%. The existence of MgZnCu Laves phase can effectively improve the heat resistance and elevated temperature properties of the alloy. The alloy with 1.5% Cu has better mechanical properties at 200 ℃:tensile strength 130 MPa and elongation 18.5%. The creep test of the alloys at 200 ℃ and 50 MPa for 102 h indicates that Mg3.5Zn0.6Gd alloy reinforced with quasicrystal has better creep properties than AE42,which can be further improved with the introduction of Laves phase in the alloy.更多还原

【Abstract】 One kind of Mg3.5Zn0.6Gd-based alloy strengthened with quasicrystals was designed,and the effect of alloying elements on microstructure and mechanical properties of as-cast Mg-Zn-Gd alloy at room temperature and elevated temperatures were studied. The results indicate that MgZnCu Laves phase,which coexists with quasicrystal at grain boundary,emerges with the addition of copper element in Mg-Zn-Gd alloy. The strength of alloys exhibits the parabola curve with the increase of copper content. The alloy with 1.5%(mole fraction) Cu shows better mechanical properties at room temperature:tensile strength 176 MPa,yield strength 176 MPa and elongation 6.5%. The existence of MgZnCu Laves phase can effectively improve the heat resistance and elevated temperature properties of the alloy. The alloy with 1.5% Cu has better mechanical properties at 200 ℃:tensile strength 130 MPa and elongation 18.5%. The creep test of the alloys at 200 ℃ and 50 MPa for 102 h indicates that Mg3.5Zn0.6Gd alloy reinforced with quasicrystal has better creep properties than AE42,which can be further improved with the introduction of Laves phase in the alloy.更多还原