Presentation Title

Effect of Aluminum on Co2NiGa High Temperature Ferromagnetic Shape Memory Alloys

Start Date

November 2016

End Date

November 2016

Location

MSE 103

Type of Presentation

Oral Talk

Abstract

Martensitic microstructure and the mechanical properties of inserting small amounts of 99.9% pure aluminum into cast Heusler alloy, Co50Ni25Ga25, were investigated in this study. The aluminum replaced the at. % of gallium from 0 to 3%, in 0.5% increments to form the Co50Ni25Ga25-xAlx alloy. As previously discovered, Co2NiGa alloys are found to exhibit ferromagnetic shape memory behavior much like Ni2MnGa alloys, but also retains a high transformation temperatures. The Cobalt within this alloy is known to enhance the ductility due to the high presence of the gamma phase. Although this alloy seems promising in FSM alloys; much of the problems with the alloy is found with its brittle nature. This present study depicts the gamma phase behavior and the changes with ductility of Co2NiGa when aluminum is introduced. Martensitic microstructure has been investigated using optical microscopic analysis and the hardness was determined using a Rockwell B 100kg ball indenter. By reducing the gamma phase with the addition of aluminum, the hardness was increased significantly and displayed a large change within the gamma phase due to the aluminum introducing more martensite. The 0.5% increments of aluminum that were added into Co50Ni25Ga25-xAlx resulted in minimal changes within the alloy in every analysis aspect. The future study will continue to investigate the effect of heat treatment and different cooling methods in Co50Ni25Ga25-xAlx Alloy.

Keywords: Ferromagnetic Shape Memory Alloys, Co-Ni-Ga-Al, Martensitic Mirostructuer,

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Nov 12th, 3:45 PM Nov 12th, 4:00 PM

Effect of Aluminum on Co2NiGa High Temperature Ferromagnetic Shape Memory Alloys

MSE 103

Martensitic microstructure and the mechanical properties of inserting small amounts of 99.9% pure aluminum into cast Heusler alloy, Co50Ni25Ga25, were investigated in this study. The aluminum replaced the at. % of gallium from 0 to 3%, in 0.5% increments to form the Co50Ni25Ga25-xAlx alloy. As previously discovered, Co2NiGa alloys are found to exhibit ferromagnetic shape memory behavior much like Ni2MnGa alloys, but also retains a high transformation temperatures. The Cobalt within this alloy is known to enhance the ductility due to the high presence of the gamma phase. Although this alloy seems promising in FSM alloys; much of the problems with the alloy is found with its brittle nature. This present study depicts the gamma phase behavior and the changes with ductility of Co2NiGa when aluminum is introduced. Martensitic microstructure has been investigated using optical microscopic analysis and the hardness was determined using a Rockwell B 100kg ball indenter. By reducing the gamma phase with the addition of aluminum, the hardness was increased significantly and displayed a large change within the gamma phase due to the aluminum introducing more martensite. The 0.5% increments of aluminum that were added into Co50Ni25Ga25-xAlx resulted in minimal changes within the alloy in every analysis aspect. The future study will continue to investigate the effect of heat treatment and different cooling methods in Co50Ni25Ga25-xAlx Alloy.

Keywords: Ferromagnetic Shape Memory Alloys, Co-Ni-Ga-Al, Martensitic Mirostructuer,