Development of texture-controlled bulky actuator/sensor materials by combining rapid-solidified fiber/ribbon elements and spark plasma sintering joining(SPSJ)

The authors have showed that rapid-solidified (RS) melt-spun fiber/ribbon/foil type samples have very often strongly textured fine columnar grains, and those can have very high performance of the metallic actuator/sensor properties. However, as for the applications of these sample materials in smart material systems, the developed rapid-solidified samples are thought to be inevitably too small force to move the machines and structures in the engineering field. In this paper, we propose one novel material processing technique that can produce the bulk type solid-state actuator/sensor materials by combing the rapid-solidified fiber/ribbon and short time spark plasma sintering/joining (SPS) method. The produced samples, both 1) the disk-type sample from stacked layers of RS-ribbons and 2)the sintered compact from ball-milled RS-fibers of shape memory Ti50Ni40Cu10 (NITINOL) alloy, showed clear thermoelastic phase transformation by DSC evaluation as well as shape recovery. The same approach was also tried for making bulky magnetostrictive FeGa(Galfenol) alloy systems from stacked FeGa ribbons. Laminated FeGa ribbons maintained large magnetostriction of about 100-200ppm under increasing stressed condition as much as in the case of the strongly textured ribbon sample.