微量Ca、Y元素对AZ91镁合金动态再结晶及力学性能的影响
|
摘要
为同步提升AZ91镁合金强度及延性,研究了微量Ca、Y元素对AZ91镁合金热变形过程中动态再结晶及力学性能的影响。结果表明:Ca、Y元素的引入减少了Al元素在AZ91镁合金中的偏聚,减少了Mg_(17)Al_(12)相的动态析出,从而抑制了低温热变形过程中的动态再结晶,同时细小弥散分布的Al_2Y相在高温时促进了动态再结晶的发生。Ca、Y元素复合添加,引入大量弥散分布的Al_2Y,使完全再结晶后的组织更加细小,提升了力学性能。AZ91+Ca+Y镁合金673 K热压后室温压缩延伸率和强度分别达到了16.5%和392.55 MPa,比AZ91镁合金分别提升了16.2%和8.56%。
To improve both the strength and ductility of AZ91 magnesium alloy, effects of Ca and Y elements on the evolution of AZ91 magnesium alloy were studied. The results showed that the introduction of Ca and Y reduced Al clustering in AZ91 magnesium alloy, as well as dynamic precipitation of Mg_(17)Al_(12) phase, thus inhibited dynamic recrystallization during thermal deformation at low temperatures, while the small dispersed Al_2Y phase promoted the occurrence of dynamic recrystallization at high temperatures. A mixed addition of Ca and Y introduced a large number of dispersed Al_2Y, which made the grains after complete recrystallization even smaller and thus strengthened the mechanical properties. The elongation and strength of AZ91+Ca+Y magnesium alloy after thermal compression under 623 K were 16.5% and 392.55 MPa, respectively, indicating 16.2% and 8.56% higher than those of AZ91 magnesium alloy.
To improve both the strength and ductility of AZ91 magnesium alloy, effects of Ca and Y elements on the evolution of AZ91 magnesium alloy were studied. The results showed that the introduction of Ca and Y reduced Al clustering in AZ91 magnesium alloy, as well as dynamic precipitation of Mg_(17)Al_(12) phase, thus inhibited dynamic recrystallization during thermal deformation at low temperatures, while the small dispersed Al_2Y phase promoted the occurrence of dynamic recrystallization at high temperatures. A mixed addition of Ca and Y introduced a large number of dispersed Al_2Y, which made the grains after complete recrystallization even smaller and thus strengthened the mechanical properties. The elongation and strength of AZ91+Ca+Y magnesium alloy after thermal compression under 623 K were 16.5% and 392.55 MPa, respectively, indicating 16.2% and 8.56% higher than those of AZ91 magnesium alloy.
引文
[1]Che C,Cai Z,Yang X,et al.The effect of co-addition of Si,Ca and REon microstructure and tensile properties of as-extruded AZ91 alloy[J].Materials Science&Engineering A,2017,705:282-290.
[2]Poliak E I,Jonas J J.Initiation of Dynamic Recrystallization in Constant Strain Rate Hot Deformation[J].Isij International,2007,43(5):684-691.
[3]Li P,Tang B,Kandalova E G.Microstructure and properties of AZ91D alloy with Ca additions[J].Materials Letters,2005,59(6):671-675.
[4]Li S S,Tang B,Zeng D B.Effects and mechanism of Ca on refinement of AZ91D alloy[J].Journal of Alloys&Compounds,2007,437(1):317-321.
[5]Hao H,Liu X,Fang C,et al.Effect of in-situ Al2Y particles on the as-cast/as-rolled microstructure and mechanical properties of AZ31 alloy[J].Materials Science&Engineering A,2017,689:35-37.
[6]Jia R,Zhang M,Zhang L,et al.Correlative change of corrosion behavior with the microstructure of AZ91 Mg alloy modified with Y additions[J].Journal of Alloys&Compounds,2015,634:263-271.
[7]Dong Qiu,Ming-xing Zhang,Patrick M Kelly.Crystallography of heterogeneous nucleation of Mg grains on Al2Y nucleation particles in an Mg-10 wt.%Y alloy[J].Scripta Materialia,2009,61(3):312-315.
[2]Poliak E I,Jonas J J.Initiation of Dynamic Recrystallization in Constant Strain Rate Hot Deformation[J].Isij International,2007,43(5):684-691.
[3]Li P,Tang B,Kandalova E G.Microstructure and properties of AZ91D alloy with Ca additions[J].Materials Letters,2005,59(6):671-675.
[4]Li S S,Tang B,Zeng D B.Effects and mechanism of Ca on refinement of AZ91D alloy[J].Journal of Alloys&Compounds,2007,437(1):317-321.
[5]Hao H,Liu X,Fang C,et al.Effect of in-situ Al2Y particles on the as-cast/as-rolled microstructure and mechanical properties of AZ31 alloy[J].Materials Science&Engineering A,2017,689:35-37.
[6]Jia R,Zhang M,Zhang L,et al.Correlative change of corrosion behavior with the microstructure of AZ91 Mg alloy modified with Y additions[J].Journal of Alloys&Compounds,2015,634:263-271.
[7]Dong Qiu,Ming-xing Zhang,Patrick M Kelly.Crystallography of heterogeneous nucleation of Mg grains on Al2Y nucleation particles in an Mg-10 wt.%Y alloy[J].Scripta Materialia,2009,61(3):312-315.