Fatigue tests of Ni-P amorphous alloy microcantilever beams

Maekawa, Shizuya; Takashima, Kazuki; Shimojo, M.; Higo, Y.; Sugiura, S.; Pfister, Bruno; Swain, Michael V.

doi:10.1109/imnc.1999.797512

Cited by 5 publications

(4 citation statements)

References 4 publications

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“…Both in situ and ex-situ configurations are present in the literature, especially coupled with simple structures as microbeams and microcantilevers. In [21,22] polysilicon notched beams are tested by means of resonant plates vibrating in-plane and comb-drives for motion detection; fatigue tests on single crystal specimens [23] and amorphous alloys [24] are proposed. Some examples of ex-situ configurations are represented by [25], where an electrical actuation and an external load cell for the measure of the load intensity are used to test microcantilever specimens; silicon nitride thin films are tested in [26], while in [27] a mechanical testing machine is developed ad used for testing on single crystal silicon specimens.…”

Section: Introductionmentioning

confidence: 99%

Mechanical fatigue analysis of gold microbeams for RF-MEMS applications by pull-in voltage monitoring

Pasquale

Somà

Ballestra

2009

Analog Integr Circ Sig Process

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This work is focused on the reliability of gold microcantilevers under the effect of mechanical fatigue. A dedicated device for testing the material is designed and built; the material degradation is monitored during the tests by means of a novel technique based on the control of the pull-in voltage of the device, which was demonstrated to be related to the loss of mechanical strength. The fatigue effect is produced through the excitation of the device at a frequency near the resonance; the excitation frequency and the time of actuation are used as a counter for the number of cycles. The lifetime of the device is measured under variable levels of vibration amplitudes; the number of cycles to failure is estimated within a specific range of actuation voltages by means of the Wöhler diagram obtained by experiments. The fatigue limit is also estimated following the stair-case method.

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Section: Introductionmentioning

confidence: 99%

Mechanical fatigue analysis of gold microbeams for RF-MEMS applications by pull-in voltage monitoring

Pasquale

Somà

Ballestra

2009

Analog Integr Circ Sig Process

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“…In particular, fracture toughness and fatigue properties of micro‐sized elements are important to enable reliable design, because even a micro‐ or a nano‐sized flaw may provide a stress concentration site leading to crack initiation. Many investigations have therefore been carried out to examine the fracture and fatigue of thin films and micro‐sized components in MEMS/MST devices 2–14 …”

Section: Introductionmentioning

confidence: 99%

Fatigue and fracture of a Ni–P amorphous alloy thin film on the micrometer scale

Takashima

Higo

2005

Fatigue Fract Eng Mat Struct

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A B S T R A C T Fracture and fatigue tests have been performed on micro-sized specimens for microelectromechanical systems (MEMS) or micro system technology (MST) applications. Cantilever beam type specimens with dimensions of 10 × 12 × 50 µm 3 , approximately 1/1000th the size of ordinary-sized specimens, were prepared from a Ni-P amorphous thin film by focused ion beam machining. Fatigue crack growth and fracture toughness tests were carried out in air at room temperature, using a mechanical testing machine developed for micro-sized specimens. In fracture toughness tests, fatigue pre-cracks were introduced ahead of the notches. Fatigue crack growth resistance curves were obtained from the measurement of striation spacing on the fatigue surface, with closure effects on the fatigue crack growth also being observed for micro-sized specimens. Once fatigue crack growth occurs, the specimens fail within one thousand cycles. This indicates that the fatigue life of micro-sized specimens is mainly dominated by a crack initiation process, also suggesting that even a micro-sized surface flaw may be an initiation site for fatigue cracks which will shorten the fatigue life of micro-sized specimens. As a result of fracture toughness tests, the values of plane strain fracture toughness, K IC , were not obtained because the criteria of plane strain were not satisfied by this specimen size. As the plane strain requirements are determined by the stress intensity, K , and by the yield stress of the material, it is difficult for micro-sized specimens to satisfy these requirements. Plane-stressand plane-strain-dominated regions were clearly observed on the fracture surfaces and their sizes were consistent with those estimated by fracture mechanics calculations. This indicates that fracture mechanics is still valid for such micro-sized specimens. The results obtained in this investigation should be considered when designing actual MEMS/MST devices.

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“…Shear testing can be performed by loading the end of a post with a probe [9]. Bending tests are performed by deflecting cantilever beams or membranes [10][11][12], bending the test material [13] or bending the substrate on which the specimen is bonded [14]. Torsional testing is performed on submicron single crystal silicon by using an electrostatically actuated comb drive [15].…”

Section: Introductionmentioning

confidence: 99%

“…Adhesion tests are performed using a double cantilever, in which the two materials are 'peeled' apart [16]. These various tests and techniques are also applied to test the fatigue characteristics [1,2,4,10,11,13] and reliability [5,14].…”

Section: Introductionmentioning

confidence: 99%

Micro-structure mechanical failure characterization using rotating Couette flow in a small gap

Blanchard¹,

Ligrani²,

Gale³

et al. 2005

J. Micromech. Microeng.

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A new method for testing the failure rates of micro-mechanical structures is presented. The technique uses Couette flow in a narrow-gap channel to induce different forces and loading on an array of structures. The Couette flow is induced by a rotating disc, which allows multiple devices to be tested at different designed stress levels depending on rotation speed and radial position. As an example, SU-8 micro-structures are used to present a general testing procedure that can be applied to other components. The forces acting on the micro-structures are due to fluid shear stress, centrifugal forces from rotation and form drag, all of which are characterized as they vary with radial position for one rotation rate. One series of tests with a single circumferential row of identical micro-structures is performed to determine the relative importance of these forces on revolutions to failure and failure rate of the structures in the row. Two additional series of tests are conducted to determine the effects of also adding unsteady loading from wakes to the structures. This unsteady loading from wakes is induced by time-varying velocity and pressure variations, which are imposed when additional rows of micro-structures are placed at smaller radial positions compared to the row being tested. Weibull failure rate approaches are used to provide information on failure rate as dependent upon cumulative revolutions. As such, the testing approach is useful for failure characterization of thin-film adhesion, self assembled nano-layers and micro-mechanical structures.

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Fatigue tests of Ni-P amorphous alloy microcantilever beams

Cited by 5 publications

References 4 publications

Mechanical fatigue analysis of gold microbeams for RF-MEMS applications by pull-in voltage monitoring

Mechanical fatigue analysis of gold microbeams for RF-MEMS applications by pull-in voltage monitoring

Fatigue and fracture of a Ni–P amorphous alloy thin film on the micrometer scale

Micro-structure mechanical failure characterization using rotating Couette flow in a small gap

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