Observation of linear defects in Al particles below 7 nm in size

An as-solidified structure of an Al-based ribbon sample produced by the melt-spinning technique was studied by x-ray diffractometry and transmission electron microscopy. The addition of Pd to Al-Y-Ni-Co alloys caused formation of the highly dispersed primary α-Al nanoparticles about 3–5 nm in size homogeneously embedded in the glassy matrix upon solidification. The first direct observation of microstrain and dislocations quenched in nanoparticles with a size below 7 nm is provided.

Rapid-Solidification Effect on Magnetostriction in Iron-based Ferromagnetic Shape Memory Alloy

ABSTRACTFe-29.6at%Pd ferromagnetic shape memory alloy (FSMA) ribbon formed by rapidly solidified, melt-spinning methods is expected to be useful as a new type of material which shows giant magnetostriction as well as quick response. The giant magnetostriction in the rolling direction depends strongly on applied magnetic-field direction and has a maximum value of 8×10-4 when the field is normal to the surface. This phenomenon is caused by the rearrangements of activated martensitic twin variants. The inverse phase transformation temperatures (As) obtained from Laser micrographs and magnetization vs. temperature curve are ∼307 K and 400∼440 K, respectively. We analyze magnetostriction, magnetic property and crystal structure of Fe-29.6at%Pd bulk sample before rapid solidification and the ribbon sample. From these results, it can be concluded that remarkable anisotropy of giant magnetostriction of ribbon sample is caused by the fine structure formed by the melt-spinning method. It may be possible to apply this method successfully to other FSMA and Ni2MnGa, which is difficult to manufacture owing to its brittleness.