On the formation of deformation bands in fatigued copper single crystals

Li, S. X.; Li, X. W.; Zhang, Z. F.; Wang, Z. G.; Lu, K.

doi:10.1080/01418610208239637

Cited by 22 publications

(4 citation statements)

References 30 publications

(5 reference statements)

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“…Reorientation is consistent with a recent analysis of slip asymmetry in cyclic deformation of fcc crystals [8], which showed that for the case of fully reversed loading, a single crystal reorients such that during the tensile half-cycle, the loading axis rotates towards the primary slip direction, [011], and during the compressive half-cycle, it rotates towards the normal to the primary slip plane, ) 1 1 1 ( . In particular, surface topography was observed to occur in only selected regions of stressed lines, and only certain grains showed growth and reorientation.…”

Section: Thermomechanical Fatigue Of Al-1si Interconnectssupporting

confidence: 89%

Microstructure Evolution During Electric Current Induced Thermomechanical Fatigue of Interconnects

et al. 2005

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We demonstrate the evolution of microstructure and deformation associated with the use of electrical methods for evaluating mechanical reliability of patterned interconnects on rigid substrates. Thermomechanical fatigue in aluminum and copper interconnects was induced by means of low frequency (100 Hz), high density (> 10 MA/cm 2 ) alternating currents, which caused cyclic Joule heating and associated thermal expansion strains between the metal lines and oxidized silicon substrate. The failure mechanism involved formation of localized plasticity, which caused topography changes on the free surfaces of the metal, leading to open circuit eventually taking place by melting at a region of severely reduced cross-sectional area. Both aluminum and copper responded to power cycling by deforming in a manner highly dependent upon variations in grain size and orientation. Isolated patches of damage appeared early within individual grains or clusters of grains, as determined by a quasi in situ scanning electron microscopy and automated electron backscatter diffraction measurement. With increased cycling, the extent of damage became more severe and widespread. We document some examples of the types of damage that mechanically confined interconnects exhibited when subjected to thousands of thermal cycles, including growth and re-orientation of grains in a systematic manner. We observed in the case of Al-1Si certain grains increasing by nearly an order of magnitude in size, and reorienting by greater than 30°. The suitability of electrical methods for accelerated testing of mechanical reliability is also discussed.

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Section: Thermomechanical Fatigue Of Al-1si Interconnectssupporting

confidence: 89%

Microstructure Evolution During Electric Current Induced Thermomechanical Fatigue of Interconnects

et al. 2005

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“…DBII are bands of localized deformation along $ 101 È É planes, perpendicular to the more common DBI deformation bands formed along {111} planes of the primary active slip system. DBI and DBII develop due to a gradual increase of lattice rotations and therefore they often appear together, in conjugate orientations related to each other, and are Philosophical Magazine 273 observed in a broad range of orientations including single and double slip crystals [14,24,25]. Veins, cells and dislocation wall structures are the most common patterns in the h111i region of orientations and they appear in the order of increasing strain amplitude [25,26].…”

Section: Introductionmentioning

confidence: 97%

Latent hardening effects in low cycle fatigue of copper single crystals

Niewczas

2013

Philosophical Magazine

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Latent hardening produced by different dislocation patterns in fatigued copper single crystals and the stability of these structures under the change of dominant slip mechanism have been studied under conditions of secondary fatigue at room temperature. Due to the larger anisotropy of the dislocation substructure, easy glide orientations of single crystals produce stronger latent hardening in non-coplanar slip systems than multiple slip orientations. There is no correlation between latent hardening ratios for different slip systems and the fatigue behavior of the secondary samples. The secondary samples may exhibit hardening or softening, depending on the relation between saturation stress of the secondary samples and the latent hardening produced by the primary substructure in the latent slip systems. The pre-saturation region in single crystals is strongly dependent on the pre-existing dislocation substructure and the slip systems operating during secondary fatigue. The saturation stress is independent of the fatigue history and the microstructure and is controlled by the crystallographic orientation of the samples and the scale of the dislocation pattern developed at saturation.

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“…The strain ranges realized in the cyclic torsion tests to be reported exceeded logarithmic strains of 0.1. Not many LCF examinations using such large cyclic strains are available in the literature for pure copper . The LCF behaviour will be explained in this study on the basis of heat generation and microstructural changes.…”

Section: Introductionmentioning

confidence: 99%

“…Not many LCF examinations using such large cyclic strains are available in the literature for pure copper. [13][14][15][16][17] The LCF behaviour will be explained in this study on the basis of heat generation and microstructural changes.…”

Section: Introductionmentioning

confidence: 99%

Ultra‐low cycle torsion fatigue of annealed copper

Hofmann

Riedle

Altenberger

et al. 2015

Fatigue Fract Eng Mat Struct

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Torsion experiments show that pure annealed copper is able to withstand very high plastic strain amplitudes when it is loaded cyclically with less than 30 cycles to failure. Under these ultra‐low cycle fatigue conditions, the performance of copper is significantly better than that of the annealed steels A36 and AISI 304, which were also tested in this study for comparison. The dependence of fatigue life on strain range can be described by a power law. In the case of an initial overloading, fatigue life can be estimated using the Palmgren–Miner rule. The long low cycle fatigue life of copper is explained by a thermally activated softening mechanism which takes place while the material heats up as a result of the cyclically repeated plastic deformation. The softening is accompanied by a change in microstructure. The low cycle fatigue properties of copper can be utilized for designing hysteretic dampers for seismic protection.

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On the formation of deformation bands in fatigued copper single crystals

Cited by 22 publications

References 30 publications

Microstructure Evolution During Electric Current Induced Thermomechanical Fatigue of Interconnects

Microstructure Evolution During Electric Current Induced Thermomechanical Fatigue of Interconnects

Latent hardening effects in low cycle fatigue of copper single crystals

Ultra‐low cycle torsion fatigue of annealed copper

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