纳米颗粒增强镍基MEMS器件材料的蠕变性能研究

利用同步辐射LIGA微铸复合工艺,将纳米氧化物增强颗粒复合到微电子机械系统(MEMS)结构材料中。制作了专用夹具,采用微力材料试验机测量了纳米Al2O3颗粒增强镍基复合材料的强度为1GPa;将恒加载速率/载荷法和恒载荷法相结合,利用纳米压痕仪测量了该材料的室温蠕变速率敏感指数m。结果表明,LIGA复合技术得到的纳米颗粒增强镍基复合材料具有较高的强度;MEMS器件材料在室温下会发生蠕变;材料在相同压深下最大载荷不随加载速率而改变,加载段粘弹性和粘塑性变形极少;主要由局部高应力导致压痕蠕变;材料的蠕变速率敏感指数m值为0.004,说明纳米Al2O3颗粒可有效增强基体材料的抗蠕变能力;且不同恒.P/P下获得的m值基本相同,表示此种材料对加载速率不敏感。

On the Creep Properties of Nano-particle Reinforced Nickel-matrix Composites of MEMS Microstructures

Structure material of MEMS was combined with nano-oxide particles by synchrotron radiation LIGA microcasting technics. The strength of Al₂O₃ nano-particle reinforced nickel-matrix composite is 1GPa, which is measured by Microtester with special fixture. Creep rate sensitivity index m of the composite at room temperature was measured by nanoindentation creep test combining the constant loading rate/load and the constant load test. Results show that nano-particle reinforced composite fabricated by LIGA process has high strength; material of MEMS microstructure presents creep behavior at room temperature; the maximum load at indentation depth of 1500nm is independent on loading rate, little viscoelastic and viscoplastic deformation took place during loading process; the indentation creep occurred due to the local high stress underneath the indenter; the average value of m is 0.004, which indicates that Al₂O₃ nano-particle has effectively reinforced the composite creep-resistating capacity. It is also found that the values of m obtained by different constants P·/P are basically identical, which indicates the insensitivity to loading conditions of this material.