| Budget Amount *help |
¥3,370,000 (Direct Cost: ¥3,100,000、Indirect Cost: ¥270,000)
Fiscal Year 2011: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2010: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2009: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Research Abstract |
Heusler alloys such as Ni-Mn-Ga and Ni-Mn-In alloys have received much attention as ferromagnetic shape memory alloys and metamagnetic shape memory alloys. These alloys are formed the solid solution of bcc-base ordered structure at high temperature in the composition range from NiMn-B2 phase to Ni2MnX-L21 phase. This bcc-base ordered phase transform to the martensite phase with unique magnetic properties. In the case of alloys with Al, Ga, In, Sb of metalloid groups, the stability of bcc ordered structure have been studied well, but in the case of Si, Ge, Pb, Bi in the same metalloid groups, those are not clarified yet. In this study, Ni59Mn50-xXx(X : Si, Ge, Pb, Bi)was prepared and the phase stability of these alloys in the temperature range from 850. C to 1000. C was investigated. Alloys added small amount of Si and Ge showed the martensitic structure, and the solubility of Si and Ge in the NiMn-B2 structure is 4 at%and 7at%, respectively. Both Ni50Mn35Si15 and Ni50Mn35Ge15 alloys showed the single-phase structure. But the crystalline structure of these alloys is. 2 phase with Ni3Mn2Si2 structure not solid solution phase with bcc ordered structure. In the Ni-Mn-Ge system, 1, 2, T were newly founded. In the case of alloys with Pb and Bi, the solubility of these elements in NiMn-B2 phase is less than 1 at%and the structure of the martensite phase are 2M structure
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