Fatigue deformation

BeardmoreP, RabinowitzS (1975) Fatigue deformation of polymers. In Arsenault RJ (ed) Treati on materials science and technology, vol 6, Academic Press, New York... 

A typical fracture surface of fibers with a mirror and hackle feature in SiC/SiC ceramics is shown in Fig. 7.24. The cyclic softening observed in SiC/SiC occurs either under stress control or strain control. Since this observation is crack initiation- and propagation-related, it is possible that similar phenomena may be more frequent after softening during fatigue deformation. The Manson-Coffin... 

Examples of dislocation structures after fatigue deformation appear in a series of microstructures (Figs. 7.55-7.59) obtained by TEM. Subramanian [27] claims that these dislocation substructures are similar to that of unidirectionaUy-stressed MgO. The micrographs presented below are of single-crystal magnesia which underwent a large number of cycles (in the millions) of low strain amplitude. The maximum strain was about 0.1 % per cycle. The characteristics of the dislocation structure in MgO, having a rock-salt structure, is as follows ... 

In the contact area between part and counter part elementary friction and wear mechanisms such as adhesion, abrasion, surface fatigue, deformation, elastic hysteresis and damping, tribochemical reactions etc. may occur. These mechanisms are overlapping in the temporal and spatial undetectable real material contact area. In addition highly formulated lubricants, which are mainly used with highly stressed engine elements, exert influence on tribochemical reactions inside and outside of the tribological contact. ... 

S.M.L.Sastiy and H.A Lipsitt, Fatigue Deformation of TiAl Base Alloys, MetaU. Thins. A, Vol 8,1977, p 299... 

A brief synopsis will be presented of fatigue deformation the reader is referred to more detailed treatises on this subject in Ref 29-31. Fatigue deformation results when a cyclic stress or... 

A number of material properties (e.g., elastic modulus, Poisson s ratio, yield stress, activation energy of creep, etc.) are included as parameters within such an equation. The second task is to map the magnitude of fatigue deformation throughout the solder joint configuration. The latter requirement is accomplished by setting up finite element meshes of the various solder... 

FIG. 30 Contour map of Pb-rich phase coarsening in a 37Pb-63Sn chip capacitor solder joint predicted by a computational model. The Pb-rich phase size (coarsening) is the metric of fatigue deformation in the solder. The cycling conditions were 6 cycles temperature limits of —50 C and 80°C ramp rates of 6°C/sec, and dwell times of 10 min. (Courtesy of Sandia National Laboratories.)... 

Another type of reinforcement involves the addition of particles which have a low solubihty and diffusivity in Sn or which do not react with Sn. Examples of this type of reinforcement are Fe particles [29] and oxide particles like AI2O3 or Ti02 [27]. Their utilization serves several purposes. Proper choice of reinforcement additions allows hard, uniformly distributed, noncoarsening particles to be introduced in a matrix. Current efforts include incorporation of nanosized particles as reinforcements [26,30]. Well-dispersed reinforcements serve as obstacles to grain growth, crack growth, and dislocation motion to resist solder creep and fatigue deformation [18,26,29]. 

Guo, C.G. Sastry, S.M.L. Jerina, K.L. Fatigue deformation of in-situ composite solders. 1st IntT... 

---