不同FSP转速处理的车减震材料用Mg-Zn-Zr合金超塑性变形分析
|
摘要
对车减震材料用Mg-Zn-Zr合金进行500～1500 r·min~(-1)转速搅拌摩擦加工(FSP)处理,并对合金超塑性变形过程的晶粒尺寸、微观形貌、第二相组织进行分析。研究结果表明:经过FSP后,在母材中形成了弥散分布状态的细小第二相组织。当FSP转速提高后,显著改善镁合金的第二相颗粒细化,并形成均匀弥散分布。在合金中存在弥散相β,有效保证了合金在应变速率下的良好超塑性。FSP会引起合金发生明显的动态再结晶现象,当FSP转速提高后,合金中形成了更大的晶界错位角,合金晶界分布结果和随机晶界分布差异性变小。所有FSP转速下合金伸长率都达到200%以上,表现出良好的超塑性。当FSP转速增大后,合金最佳应变速率与伸长率都会显著提高,并且变形温度也会上升。各合金经过超塑性变形后都发生了晶界滑移,而且当FSP转速提高,晶粒发生了明显细化。
The Mg-Zn-Zr alloy used for vehicle shock-absorbing material was processed by friction stir processing( FSP) at 500-1500 r·min~(-1) rotation speed,and the grain size,micro-morphology and the second phase structure of alloy during the superplastic deformation process were analyzed. The results show that the second phase microstructure is formed in the base metal as the dispersion distribution after FSP,and with the increasing of FSP rotation speed,the second phase particle refinement of magnesium alloy is significantly improved to form the uniform dispersion distribution. Then,the dispersion phase β existing in the alloy effectively guarantees the good superplasticity of alloy under strain rate,and FSP causes the obvious dynamic recrystallization of alloy. When the rotation speed of FSP increases,a larger grain boundary dislocation angle occurs in the alloy,and the difference between the results of grain boundary distribution and the random grain boundary distribution decreases. Furthermore,the elongation of alloy at all FSP rotation speeds is over 200% to show the good superplasticity. When the rotation speed of FSP increases,the optimum strain rate and the elongation of alloy increase significantly,and the deformation temperature also increases. After superplastic deformation,the grain boundary slip occurs in all alloys,and when the FSP rotation speed is increased,the grains are obviously refined.
The Mg-Zn-Zr alloy used for vehicle shock-absorbing material was processed by friction stir processing( FSP) at 500-1500 r·min~(-1) rotation speed,and the grain size,micro-morphology and the second phase structure of alloy during the superplastic deformation process were analyzed. The results show that the second phase microstructure is formed in the base metal as the dispersion distribution after FSP,and with the increasing of FSP rotation speed,the second phase particle refinement of magnesium alloy is significantly improved to form the uniform dispersion distribution. Then,the dispersion phase β existing in the alloy effectively guarantees the good superplasticity of alloy under strain rate,and FSP causes the obvious dynamic recrystallization of alloy. When the rotation speed of FSP increases,a larger grain boundary dislocation angle occurs in the alloy,and the difference between the results of grain boundary distribution and the random grain boundary distribution decreases. Furthermore,the elongation of alloy at all FSP rotation speeds is over 200% to show the good superplasticity. When the rotation speed of FSP increases,the optimum strain rate and the elongation of alloy increase significantly,and the deformation temperature also increases. After superplastic deformation,the grain boundary slip occurs in all alloys,and when the FSP rotation speed is increased,the grains are obviously refined.
引文
[1]Al-Samman T.Modification of texture and microstructure of magnesium alloy extrusions by particle-stimulated recrystallization[J].Mater.Sci.Eng.,2013,560:561-566.
[2]白云.挤压温度对汽车用新型镁合金组织和性能的影响[J].锻压技术,2018,43(4):146-148.Bai Y.Influence of extrusion temperature on microstructure and properties of new magnesium alloy for automobile[J].Forging&Stamping Technology,2018,43(4):146-148.
[3]Hou X L,Zhai Y X,Zhang P,et al.Rare earth texture analysis of rectangular extruded Mg alloys and a comparison of different alloying adding ways[J].Rare Met.,2016,35(11):850-857.
[4]张晓旭,杜子学.等通道角轧制对汽车车身用轻质镁合金板微观组织与力学性能的影响[J].锻压技术,2017,42(3):154-158.Zhang X X,Du Z X.Influence of equal channel angular rolling on microstructure and mechanical properties of magnesium alloy AZ31sheet[J].Forging&Stamping Technology,2017,42(3):154-158.
[5]Padhy G K,Wu C S,Gao S.Friction stir based welding and processing technologies-processes,parameters,microstructures and applications:A review[J].J.Mater.Sci.Technol.,2018,34(1):1-38.
[6]夏显明,薛克敏,李萍,等.高压扭转对挤压态ZK60镁合金微观组织和力学性能的影响[J].锻压技术,2018,43(5):130-136.Xia X M,Xue K M,Li P,et al.Effect of high pressure torsion on microstructure and mechanical properties of extruded magnesium alloy ZK60[J].Forging&Stamping Technology,2018,43(5):130-136.
[7]杨晓敏,李明珠,董锋,等.温度及搅拌摩擦加工对AZ31镁合金力学性能的影响[J].锻压技术,2017,42(7):169-172.Yang X M,Li M Z,Dong F,et al.Influence of temperature and friction stir processing on mechanical properties of magnesium alloy AZ31[J].Forging&Stamping Technology,2017,42(7):169-172.
[8]Yang Q,Xiao B L,Ma Z Y,et al.Achieving high strain rate superplasticity in Mg-Zn-Zr alloy produced by friction stir processing[J].Scr.Mater.,2011,65(4):335-338.
[9]Abbasi M,Nelson T W,Sorensen C D.Transformation and deformation texture study in friction stir processed API X80 pipeline steel[J].Metall.Mater.Trans.,2012,43(13):4940-4946.
[10]Yang J,Wang D,Xiao B L,et al.Effects of rotation rates on microstructure,mechanical properties,and fracture behavior of friction stir-welded(FSW)AZ31 magnesium alloy[J].Metall.Mater.Trans.,2013,44(1):517-530.
[11]Chai F,Zhang D T,Li Y Y,et al.High strain rate superplasticity of a fine-grained AZ91 magnesium alloy prepared by submerged friction stir processing[J].Mater.Sci.Eng.,2013,568:40-48.
[12]Xie G M,Ma Z Y,Geng L,et al.Microstructural evolution and enhanced superplasticity in friction stir processed Mg-Zn-Y-Zr alloy[J].J.Mater.Res.,2008,23(5):1207-1213.
[2]白云.挤压温度对汽车用新型镁合金组织和性能的影响[J].锻压技术,2018,43(4):146-148.Bai Y.Influence of extrusion temperature on microstructure and properties of new magnesium alloy for automobile[J].Forging&Stamping Technology,2018,43(4):146-148.
[3]Hou X L,Zhai Y X,Zhang P,et al.Rare earth texture analysis of rectangular extruded Mg alloys and a comparison of different alloying adding ways[J].Rare Met.,2016,35(11):850-857.
[4]张晓旭,杜子学.等通道角轧制对汽车车身用轻质镁合金板微观组织与力学性能的影响[J].锻压技术,2017,42(3):154-158.Zhang X X,Du Z X.Influence of equal channel angular rolling on microstructure and mechanical properties of magnesium alloy AZ31sheet[J].Forging&Stamping Technology,2017,42(3):154-158.
[5]Padhy G K,Wu C S,Gao S.Friction stir based welding and processing technologies-processes,parameters,microstructures and applications:A review[J].J.Mater.Sci.Technol.,2018,34(1):1-38.
[6]夏显明,薛克敏,李萍,等.高压扭转对挤压态ZK60镁合金微观组织和力学性能的影响[J].锻压技术,2018,43(5):130-136.Xia X M,Xue K M,Li P,et al.Effect of high pressure torsion on microstructure and mechanical properties of extruded magnesium alloy ZK60[J].Forging&Stamping Technology,2018,43(5):130-136.
[7]杨晓敏,李明珠,董锋,等.温度及搅拌摩擦加工对AZ31镁合金力学性能的影响[J].锻压技术,2017,42(7):169-172.Yang X M,Li M Z,Dong F,et al.Influence of temperature and friction stir processing on mechanical properties of magnesium alloy AZ31[J].Forging&Stamping Technology,2017,42(7):169-172.
[8]Yang Q,Xiao B L,Ma Z Y,et al.Achieving high strain rate superplasticity in Mg-Zn-Zr alloy produced by friction stir processing[J].Scr.Mater.,2011,65(4):335-338.
[9]Abbasi M,Nelson T W,Sorensen C D.Transformation and deformation texture study in friction stir processed API X80 pipeline steel[J].Metall.Mater.Trans.,2012,43(13):4940-4946.
[10]Yang J,Wang D,Xiao B L,et al.Effects of rotation rates on microstructure,mechanical properties,and fracture behavior of friction stir-welded(FSW)AZ31 magnesium alloy[J].Metall.Mater.Trans.,2013,44(1):517-530.
[11]Chai F,Zhang D T,Li Y Y,et al.High strain rate superplasticity of a fine-grained AZ91 magnesium alloy prepared by submerged friction stir processing[J].Mater.Sci.Eng.,2013,568:40-48.
[12]Xie G M,Ma Z Y,Geng L,et al.Microstructural evolution and enhanced superplasticity in friction stir processed Mg-Zn-Y-Zr alloy[J].J.Mater.Res.,2008,23(5):1207-1213.