TiNiHf/SiO_(2)/Si shape memory film composites for bidirectional micro actuation
作者机构:Institute for Materials ScienceKiel University(CAU)KielGermany Materials Science and EngineeringUniversity of MarylandCollege ParkMDUnited States Institute of Microstructure TechnologyKarlsruhe Institute of Technology(KIT)KarlsruheGermany
出 版 物:《International Journal of Smart and Nano Materials》 (国际智能和纳米材料杂志(英文))
年 卷 期:2022年第13卷第2期
页 面:293-314页
核心收录:
学科分类:08[工学] 080502[工学-材料学] 0805[工学-材料科学与工程(可授工学、理学学位)]
基 金:Institute for Applied Materials National Science Foundation, NSF, (DGE 1840340) National Science Foundation, NSF Deutsche Forschungsgemeinschaft, DFG
主 题:Bimorph microactuator NiTiHf bistable actuator shape memory alloy thin films
摘 要:The martensitic phase transformation in Ti_(40.4)Ni_(48)Hf_(11.6) shape memory alloys is leveraged for bi-directional actuation with TiNiHf/SiO_(2)/Si *** shape memory properties of magnetron sputtered Ti_(40.4)Ni_(48)Hf_(11.6) films annealed at 635℃-5 min are influenced by film thickness and the underlying *** TiNiHf film thick-ness from 21μm to 110 nm results in the reduction of all characteristic transformation temperatures until a critical thickness is ***,Ti_(40.4)Ni_(48)Hf_(11.6) thin films as low as 220 nm show transfor-mations above room temperature when deposited on SiO_(2) buffer layer,which is of great interest in *** comparison,220 nm films on Si substrates are austenitic at room temperature,and thus not suitable for *** fatigue tests on TiNiHf/SiO_(2)/Si bimorphs demonstrate better functional fatigue characteristics than freestanding films,with an average reduction of 15℃ after 125 cycles,with tempera-ture stabilization *** bi-directional actuation results are promising in the development of bistable actuators within a PMMA/TiNiHf/Si trimorph composite,whereby the additional PMMA layer undergoes a glass transition at 105℃.With the aid of constitutive modeling,a route is elaborated on how bistable actuation can be achieved at micro-to nanoscales by showing favorable thickness combinations of PMMA/TiNiHf/Si composite.