INFLUENCE OF DEFECTS ON THE IRREVERSIBLE PHASE TRANSITION IN THE Fe- Pd DOPED WITH Co AND Mn

F. G. BONIFACICH; D. GARGICEVICH; O. A. LAMBRI; G. I. ZELADA; J. I. PÉREZ-LANDAZÁBAL; V. RECARTE; V. SÁNCHEZ-ALARCOS

Córdoba

Congreso; Congreso SAM-CONAMET-IBEROMAT 2016; 2016

The presence of BCT martensite in Fe-Pd-based ferromagnetic shape memory alloys (FSMA), which develops at lower temperatures than the martensitic transition (MT), deteriorates the shape memory properties. In a previous work performed in Fe70Pd30, it was shown that a thermal treatment above 600 K clearly stabilizes the alloy, reducing the FCT-BCT transformation temperature.In the present work, a study concerning to the stabilization possibilities of Fe67Pd30Co3 and Fe66.8Pd30.7Mn2.5 FSMA, is carried out, by means of mechanical spectroscopy (MS) and differential thermal analysis (DTA). Indeed, Fe67Pd30Co3 and Fe66.8Pd30.7Mn2.5 exhibit a lower (250 K) and a higher (310 K) MT temperature, respectively; than the Fe70Pd30. Several thermal cycles involving heating and cooling runs, up to different maximum temperatures are performed in MS and DTA in as-quenched samples.Polycrystalline ingots of nominal composition (at.%) Fe70Pd30, Fe67Pd30Co3, Fe66.8Pd30.7Mn2.5 were prepared from high purity elements by arc melting under protective Ar atmosphere. The ingots were homogenized in vacuum quartz ampoules at 1273K during 24 hours and subjected to a 30 minutes annealing treatment at 1173K in a vertical furnace, followed by quenching into iced water.