机械振动和锰铬变质对Mg_2Si/富铁A356再生铝基复合材料组织与性能的影响
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摘要
制备了12%Mg_2Si/A356-1.2%Fe(质量分数,下同)富铁再生铝基复合材料,研究了振动频率(100,150,200Hz)和变质剂锰铬质量比(0∶1,3∶7,1∶1,7∶3,1∶0)对其铸态组织和性能的影响,并对比分析了固溶+时效态复合材料和A356-0.5%Fe再生铝合金的组织和抗拉强度。结果表明:机械振动有助于细化未变质复合材料中的共晶Si相、Mg_2Si相和富铁相,促进其均匀分布,从而提高复合材料的室温抗拉强度;锰铬变质后的富铁相由针状变为鱼骨状、颗粒状或汉字状,当锰铬质量比为1∶1时,室温抗拉强度最大,为125 MPa;在振动频率200Hz、锰铬质量比1∶1条件下,固溶+时效态复合材料中形成了六角晶型α-Fe(Al_8Fe_2Si)相,而A356-0.5Fe再生铝合金中形成了单斜晶型β-Fe(Al_5FeSi)相,复合材料的室温和200,300℃高温抗拉强度均高于A356-0.5%Fe再生铝合金的。
12 wt%Mg_2 Si/A356-1.2 wt%Fe Fe-rich recycled Al matrix composite was prepared.The effects of vibration frequency(100,150,200 Hz)and Mn to Cr mass ratio(0∶1,3∶7,1∶1,7∶3,1∶0)of modifier on the as-cast microstructure and property were studied.The microstructure and tensile strength of the composite and A356-0.5 wt%Fe recycled Al alloy after solid solution and aging were analyzed and compared.The results show that the mechanical vibration helped the refinement and even distribution of eutectic Si phase,Mg_2Si phase and Fe-rich phase in the unmodified composite,resulting in the improvement of tensile strength at room temperature of the composite.After modification with Mn/Cr,the Fe-rich phase changed from needle-like to fish-bone shape,granular or chinese-character shape.When Mn to Cr mass ratio was 1∶1,the tensile strength at room temperature reached the maximum value of 125 MPa.At vibration frequency of 200 Hz and with Mn to Cr mass ratio of 1∶1,α-Fe(Al_8Fe_2Si)phase with hexagonal crystal shape was formed in the composite after solid solution and aging,while in the A536-0.5 wt%Fe recycled Al alloy formed "-Fe(Al_5FeSi)phase with monoclinic crystal shape.The tensile strength at room temperature and at 200,300 ℃ of the composite was higher than those of the A536-0.5 wt%Fe recycled Al alloy.
12 wt%Mg_2 Si/A356-1.2 wt%Fe Fe-rich recycled Al matrix composite was prepared.The effects of vibration frequency(100,150,200 Hz)and Mn to Cr mass ratio(0∶1,3∶7,1∶1,7∶3,1∶0)of modifier on the as-cast microstructure and property were studied.The microstructure and tensile strength of the composite and A356-0.5 wt%Fe recycled Al alloy after solid solution and aging were analyzed and compared.The results show that the mechanical vibration helped the refinement and even distribution of eutectic Si phase,Mg_2Si phase and Fe-rich phase in the unmodified composite,resulting in the improvement of tensile strength at room temperature of the composite.After modification with Mn/Cr,the Fe-rich phase changed from needle-like to fish-bone shape,granular or chinese-character shape.When Mn to Cr mass ratio was 1∶1,the tensile strength at room temperature reached the maximum value of 125 MPa.At vibration frequency of 200 Hz and with Mn to Cr mass ratio of 1∶1,α-Fe(Al_8Fe_2Si)phase with hexagonal crystal shape was formed in the composite after solid solution and aging,while in the A536-0.5 wt%Fe recycled Al alloy formed "-Fe(Al_5FeSi)phase with monoclinic crystal shape.The tensile strength at room temperature and at 200,300 ℃ of the composite was higher than those of the A536-0.5 wt%Fe recycled Al alloy.
引文
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[2]姜玉敬.我国再生铝工业的发展前景与展望[N].中国有色金属报,2016-12-31(3).
[3]孙德勤,周自强,费有静,等.改善废铝再生中Fe相析出形态的工艺试验[J].铸造,2017,66(4):403-407.
[4]谭喜平,宋东福,郑开宏,等.机械振动对再生铝合金组织和力学性能的影响[J].稀有金属,2014,38(2):185-192.
[5]关玉芹,杜军,吴桃泉,等.B-Cr变质对20%Mg2Si/A356-1.3%Fe再生铝基复合材料组织和性能的影响[J].中国有色金属学报,2017,27(4):684-691.
[6]吴桃泉,杜军,黄正阳,等.Mn/Cr复合变质对15%Mg2Si/再生A356-1.5%Fe基复合材料中富Fe相形态的影响[J].中国有色金属学报,2018,28(4):654-661.
[7]TAYLOR J A.Iron-containing intermetallic phases in Al-Si based casting alloys[J].Procedia Materials Science,2012,1:19-33.
[8]吴桃泉,杜军,关玉芹,等.Mg2Si/富铁A356再生铝基复合材料的组织及耐磨性研究[J].铸造,2016,65(10):970-974.
[9]SEIFEDDINE S,JOHANSSON S,SVENSSON I L.The influence of cooling rate and manganese content on theβ-Al5FeSi phase formation and mechanical properties of Al-Sibased alloys[J].Materials Science and Engineering:A,2008,490(1/2):385-390.
[10]宋东福,王顺成,郑开宏,等.Mn/Fe摩尔比对A356铸造铝合金富铁相形态的影响[J].中国有色金属学报,2015,25(7):1832-1838.