The possibility to detect the phase transformation with martensites by heating or cooling as well as stress-loading in ferromagnetic shape memory Fe-30at%Pd alloy thin foil by using magnetic Barkhausen noise (MBHN) sensor was studied. MBHN is caused by the irregular interactions between magnetic domain and thermally activated martensite twins during magnetization. In general, the envelope of the BHN voltage vs time signals in Fe-29.6at%Pd ribbon showed two peaks during magnetization, where secondary peak at intermediate state of magnetization process decreased with increasing temperature, while the BHN envelopes in pure iron (αFe) and pure nickel (Ni) did not change with increasing temperature. The variety of BHN due to the phase transformation was apt to arise at higher frequency part of spectrum during intermediate state of magnetization process and it decreased with disappearance of martensite twins. Besides, BHN increased monotonically with increasing loading stress and then, it decreased with unloading, however BHN showed large hysteresis between loading and unloading passes. Based on the experimental results from BHN measurements for both thermoelastic and stress-induced martensite phase transformations in Fe-30at%Pd ribbon samples, MBHN method seems a useful technique to non-destructive evaluation of martensite phase transformation of ferromagnetic shape memory alloy.
|ジャーナル||Proceedings of SPIE-The International Society for Optical Engineering|
|出版ステータス||Published - 2002|
ASJC Scopus subject areas
- コンピュータ サイエンスの応用