Evolution of iron-rich phases and their effect on the tensile fracture behavior of squeeze-cast Al-Cu alloys with high Fe contents
Author(s): LIN Bo, ZHANG Wei-wen, School of Mechanical Engineering, Gui Zhou University, School of Mechanical and Automotive Engineering, South China University of Technology
Pages: 47-55
Year: 2016 Issue: 12
Journal: Transactions of Materials and Heat Treatment
Keyword: iron-rich intermetallics; Al-Cu alloys; squeeze casting; mechanical property; tensile fracture behavior;
Abstract: Evolution of iron-rich phases and their effect on tensile fracture behavior of squeeze-cast Al-Cu cast alloys with different Fe contents were studied by tensile test,scanning electron microscopy(SEM),transmission electron microscopy(TEM),deep etching technique and quantitive metallograph. The results show that mechanical properties of the Al-Cu cast alloys decreases obviously with the increase of Fe content due to the increase of needle-like iron-rich phases,the increase of volume fraction and size of iron-rich of phases,and the decrease of volume fraction of precipitation particles in the(Al) matrix. The Chinese script phases α-Fe and Al6(FeMn) are less damaging to the tensile properties compared to the needle-like β-Fe. Because the cracks are usually deflected along the branches/arms of the Chinese script iron-rich phases,this makes the alloys more resistant to the crack propagation during tensile deformation. The needlelike β-Fe and Al3(FeMn) is harmful to the mechanical properties of the Al-Cu alloys,the needle-like iron-rich intermetallics resulted in stress concentration easily and acts as crack initiation sites,platelets iron-rich intermetallics impede the flow of liquid metal during the solidification. The mechanical properties of the as-cast Al-Cu alloys are improved by applied pressures for the decrease of needle-like ironrich intermetallics,the increase of aspect ratio of iron-rich intermetallics,and the refinement of iron-rich intermetallics. All these factors decreased the possibility of fracture within the iron-rich intermetallics themselves and increase the cohesion between the iron-rich intermetallics and the α(Al) matrix.
Pages: 47-55
Year: 2016 Issue: 12
Journal: Transactions of Materials and Heat Treatment
Keyword: iron-rich intermetallics; Al-Cu alloys; squeeze casting; mechanical property; tensile fracture behavior;
Abstract: Evolution of iron-rich phases and their effect on tensile fracture behavior of squeeze-cast Al-Cu cast alloys with different Fe contents were studied by tensile test,scanning electron microscopy(SEM),transmission electron microscopy(TEM),deep etching technique and quantitive metallograph. The results show that mechanical properties of the Al-Cu cast alloys decreases obviously with the increase of Fe content due to the increase of needle-like iron-rich phases,the increase of volume fraction and size of iron-rich of phases,and the decrease of volume fraction of precipitation particles in the(Al) matrix. The Chinese script phases α-Fe and Al6(FeMn) are less damaging to the tensile properties compared to the needle-like β-Fe. Because the cracks are usually deflected along the branches/arms of the Chinese script iron-rich phases,this makes the alloys more resistant to the crack propagation during tensile deformation. The needlelike β-Fe and Al3(FeMn) is harmful to the mechanical properties of the Al-Cu alloys,the needle-like iron-rich intermetallics resulted in stress concentration easily and acts as crack initiation sites,platelets iron-rich intermetallics impede the flow of liquid metal during the solidification. The mechanical properties of the as-cast Al-Cu alloys are improved by applied pressures for the decrease of needle-like ironrich intermetallics,the increase of aspect ratio of iron-rich intermetallics,and the refinement of iron-rich intermetallics. All these factors decreased the possibility of fracture within the iron-rich intermetallics themselves and increase the cohesion between the iron-rich intermetallics and the α(Al) matrix.
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