超声处理协同Er和Ce复合变质对Mg-3.2Si合金组织及性能的影响
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摘要
研究了超声处理协同稀土元素Er和Ce复合变质对过共晶Mg-3.2Si合金中组织和力学性能的影响,并探讨了其作用机理。结果表明,在过共晶Mg-3.2Si合金中,添加约0.6%(质量分数,下同)的Er时,初生Mg2Si相的尺寸由150μm减小到40μm,其形态从粗大树枝状变为不规则多面体形状;继续添加1.0%的Ce,可获得5～10μm的多面体或球状初生Mg2Si相,变质效果明显。在此基础上,超声处理可以有效改变初生Mg2Si相的形状和尺寸。当超声功率为1 200W时,可获得颗粒状的初生Mg2Si相,细化效果最佳,合金试样的抗拉强度与伸长率分别达到158MPa和4.5%。对其断口分析可知,经超声处理的合金断裂形式为解理断裂和韧窝的混合断裂形式。
Effects of ultrasonic treatment and Er-Ce compound modification on microstructure and mechanical properties of hypereutectic Mg-3.2Si alloy were investigated,and the refining mechanism was described.The results reveal that with 0.6%(mass fraction,the same below)Er addition,the size of the primary Mg2 Si phase in the Mg-3.2Si alloy is decreased from 150μm to 40μm with strucutre transformed from bulky dendritic into irregular polyhedron shape.Then adding 1.0% Ce,polyhedron primary Mg2 Si phase with size of 5～10μm can be observed in the Mg-3.2Si alloy.With the increase of ultrasonic treatment power,the morphology,size and distribution of Mg2 Si in Mg-3.2Si alloy solidified structure can be improved obviously.With ultrasonic treatment power of1 200 W,the Mg2 Si phase in the alloy is changed into granulate structure,and its tensile strength and elongation reach 158 MPa and 4.5%,respectively.The fracture morphology of the Er-Ce compound modified Mg-3.2Si alloy after ultrasonic treated is characterized by as a mixed fracture form between cleavage fracture and dimple fracture.
Effects of ultrasonic treatment and Er-Ce compound modification on microstructure and mechanical properties of hypereutectic Mg-3.2Si alloy were investigated,and the refining mechanism was described.The results reveal that with 0.6%(mass fraction,the same below)Er addition,the size of the primary Mg2 Si phase in the Mg-3.2Si alloy is decreased from 150μm to 40μm with strucutre transformed from bulky dendritic into irregular polyhedron shape.Then adding 1.0% Ce,polyhedron primary Mg2 Si phase with size of 5～10μm can be observed in the Mg-3.2Si alloy.With the increase of ultrasonic treatment power,the morphology,size and distribution of Mg2 Si in Mg-3.2Si alloy solidified structure can be improved obviously.With ultrasonic treatment power of1 200 W,the Mg2 Si phase in the alloy is changed into granulate structure,and its tensile strength and elongation reach 158 MPa and 4.5%,respectively.The fracture morphology of the Er-Ce compound modified Mg-3.2Si alloy after ultrasonic treated is characterized by as a mixed fracture form between cleavage fracture and dimple fracture.
引文
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[10]陈君,李全安,张清,等.Gd对Mg-6Al-1.2Y-0.9Nd合金组织和性能的影响[J].特种铸造及有色合金,2015,34(5):453-456.
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[13]张浩,周全,章森.超声对Mg97Y2Cu1合金凝固组织和力学性能的影响[J].特种铸造及有色合金,2015,35(8):875-878.
[14]柏世梅,尧军平,刘辉,等.稀土Er和Ce复合改性对过共晶Mg-Si合金组织与性能的影响[J].复合材料学报,2017,34(6):58-65.
[15] QIN Q D,ZHAO Y G,ZHOU W,et al.Effect of phosphorous on microstructure and growth manner of primary Mg2Si crystal in Mg2Si/Al composite[J].Materials Science and Engineering,2007,A447:186-191.
[16]唐定骧,刘余九,张洪杰,等.稀土金属材料[M].北京:冶金工业出版社,2011.
[2]胡勇,闫洪,陈国香,等.Si对原位自生Mg2Si/AM60复合材料组织及性能的影响[J].稀有金属材料与工程,2009,28(2):343-347.
[3]张金山,高义斌,裴利霞,等.P变质对Si合金化AZ91镁合金显微组织和力学性能的影响[J].中国有色金属学报,2006,16(8):1 361-1 364.
[4] PAN Y C,LIU X F,YANG H.Microstructural formation in a hypereutectic Mg-Si alloy[J].Materials Characterization,2005,55:241-247.
[5] JIANG Q C,WANG H Y,WANG Y.Modification of Mg2Si in MgSi alloys with yttrium[J].Materials Science and Engineering,2005,392:130-135.
[6] KIM J J,KIM D H,SHIN K.Modification of Mg2Si morphology in squeeze cast Mg-Al-Zn-Si alloys by Ca or P addition[J].Scripta Materialia,1999,41(3):333-340.
[7]陈晓,傅高升,钱匡武.Ca对原位自生Mg2Si/ZM5复合材料组织与性能的影响[J].中国有色金属学报,2005,15(3):410-414.
[8]杨明波,潘复生,程仁菊,等.Sr和Sb变质AZ61-0.7Si合金的铸态组织和力学性能[J].稀有金属材料与工程,2008,37(10):1 737-1 741.
[9]马宝霞,王丽萍,郭二军.镧对Mg-Si合金中Mg2Si相变质的影响[J].中国稀土学报,2008,26(1):87-91.
[10]陈君,李全安,张清,等.Gd对Mg-6Al-1.2Y-0.9Nd合金组织和性能的影响[J].特种铸造及有色合金,2015,34(5):453-456.
[11]闫洪.超声处理对原位Mg2Si/AM60复合材料的影响[J].特种铸造及有色合金,2012,32(7):657-660.
[12]蒋日鹏.超声场对高强铝合金凝固过程的影响规律与作用机理研究[D].长沙:中南大学,2014.
[13]张浩,周全,章森.超声对Mg97Y2Cu1合金凝固组织和力学性能的影响[J].特种铸造及有色合金,2015,35(8):875-878.
[14]柏世梅,尧军平,刘辉,等.稀土Er和Ce复合改性对过共晶Mg-Si合金组织与性能的影响[J].复合材料学报,2017,34(6):58-65.
[15] QIN Q D,ZHAO Y G,ZHOU W,et al.Effect of phosphorous on microstructure and growth manner of primary Mg2Si crystal in Mg2Si/Al composite[J].Materials Science and Engineering,2007,A447:186-191.
[16]唐定骧,刘余九,张洪杰,等.稀土金属材料[M].北京:冶金工业出版社,2011.