Background: MEMS-based nanomechanical testing has received much interests. However, it remains challenging to perform displacement- and force-controlled nanomechanical tests (e.g., stress relaxation and creep). Objective: We report a MEMS-based device for displacement- and force-controlled tensile testing of 1D nanomaterials using feedback control. Methods: The device consists of an electrostatic actuator, a load cell, and two differential capacitive sensors. A specimen is mounted between a fixed anchor on one side and a displacement sensor on the other side. Using a multi-channel capacitive readout, both specimen displacement and force (thus strain and stress) can be measured from the readout simultaneously, without the need of imaging that is often used for displacement measurement. Results: With the feedback control, both displacement- and force-controlled tensile testing can be achieved. The capability of the device is demonstrated in three representative tests of metallic nanowires – stress relaxation test, tensile test capturing rapid stress drop, and creep test. Conclusions: The reported MEMS device can be used for a range of tests where imaging for displacement measurement is not feasible, such as ex-situ tests, high-rate tests, and fatigue tests in different environments.

中文翻译：

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用于纳米机械测试的微机电系统：具有反馈控制的位移和力控制拉伸测试

背景：基于 MEMS 的纳米力学测试受到了广泛关注。然而，执行位移和力控制的纳米力学测试（例如，应力松弛和蠕变）仍然具有挑战性。目标：我们报告了一种基于 MEMS 的设备，用于使用反馈控制对一维纳米材料进行位移和力控制的拉伸测试。方法：该设备由一个静电致动器、一个称重传感器和两个差分电容传感器组成。试样安装在一侧的固定锚和另一侧的位移传感器之间。使用多通道电容读数，可以同时从读数中测量样本位移和力（因此应变和应力），而无需通常用于位移测量的成像。结果：通过反馈控制，可以实现位移和力控制的拉伸测试。该器件的能力在金属纳米线的三个代表性测试中得到证明——应力松弛测试、捕捉快速应力下降的拉伸测试和蠕变测试。结论：所报告的 MEMS 器件可用于位移测量成像不可行的一系列测试，例如异地测试、高速率测试和不同环境下的疲劳测试。