SHAPE-MEMORY PROPERTIES IN NI-TI SPUTTER-DEPOSITED FILM
SHAPE-MEMORY PROPERTIES IN NI-TI SPUTTER-DEPOSITED FILM
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DOI：
10.1063/1.346914
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发表时间：
1990-12-15
影响因子：
3.2
通讯作者：
STEVENSON, DA
中科院分区：
文献类型：
--
作者：
BUSCH, JD;JOHNSON, AD;STEVENSON, DA
本研究的目的是在溅射沉积的镍钛薄膜中建立形状记忆效应。这种合金，通称为Niinol，是由两种不同成分的溅射靶材制备的。使用直流磁控溅射源在玻璃衬底上沉积了厚度达10微米的薄膜。沉积的薄膜为非晶态结构，没有形状记忆。采用合适的退火工艺对非晶态薄膜进行晶化处理，并用差示扫描量热法测量了薄膜的相变特性。晶化膜的转变温度远低于母体材料。X射线衍射图表明，薄膜不是单相，而是第二相的证据。然而，退火后的薄膜表现出很强的形状记忆效应。通过应力/应变测量和物理操作来评估形状恢复情况。这些测试表明，高温阶段的持续拉应力高达480兆帕，而低温阶段的塑性变形具有特征。
The objective of this research is to establish a shape-memory effect in sputter-deposited films of nickel titanium. The alloy, generically called nitinol, was prepared from sputtering targets in two different compositions. Films were deposited up to 10 mu-m in thickness on glass substrates using a dc magnetron sputtering source. The as-deposited films were amorphous in structure and did not exhibit a shape memory. The amorphous films were crystallized with a suitable annealing process, and the transformation properties were measured using differential scanning calorimetry. The crystallized films showed transition temperatures that were much lower than those of the parent material. X-ray diffraction patterns indicated that the films were not a single phase but showed evidence of a second phase. However, the annealed films demonstrated a strong shape-memory effect. Stress/strain measurements and physical manipulation were used to evaluate the shape recovery. These tests demonstrated sustained tensile stresses of up to 480 MPa in the high-temperature phase, and a characteristic plastic deformation in the low-temperature phase.