Silicon tensile creep

Lofaj F, Wiederhorn SM, Long GG, Jemian PR (2001) Tensile Creep in the next Generation Silicon Nitride. In Singh M, Jessen T (eds) 25th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures A (Ceram Eng Sci Proc 22). Am Ceram Soc, Westerville, OH, p 167... 

Ohji T (1994) Tensile Creep Rupture And Subcritical Crack Growth of Silicon Nitride. In Hoffmann MJ, Petzow G (eds) Tailoring of Mechanical Properties of Si3N4 Ceramics. Kluwer Academic Publishers, Netherlands, p 339... 

B. J. Hockey, S. M. Wiederhorn, W. Liu, J. G. Baldoni,and S. T. Buljan, Tensile Creep of SiC Whisker-Reinforced Silicon Nitride, in Proc. 27th Auto. Tech. Dev. Contractors Coord. Meeting, Vol. P-230, Society of Automotive Engineers, Warrendale, PA, 1990, pp. 251-257. 

A typical tensile creep curve for a particulate reinforced ceramic matrix composite, siliconized silicon carbide (Si/SiC),28 is shown in Fig. 4.1. In comparison to the behavior of metals and metallic alloys, tertiary creep is suppressed in this material. There is only a slight upward curvature of the creep curve prior to failure. In many other ceramic matrix composites, tertiary... 

Fig. 4.1 Tensile creep curves for siliconized silicon carbide (Carborundum KX01). Over most of the data range, these data can be represented by a constant creep rate there is a short primary creep stage, and almost no tertiary creep. The rupture strain decreases with increasing creep rate. The strain to failure, =1.5%, indicates brittle behavior even at low rates of creep detormation. Figure from Ref. 28.

M. Giirtler and G. Grathwohl, Tensile Creep Testing of Sintered Silicon Nitride, in Proceedings of the Fourth International Conference on Creep and Fracture of Engineering Materials and Structures, Institute of Metals, London, U.K., 1990, pp. 39 408. 

Tatsuki Ohji and Yukihiko Yamauchi, Tensile Creep and Creep Rupture Behaviors of Silicon Nitride, J. Am. Ceram. Soc., 76[ 12], 3105-3112 (1993). 

Ohji, T., A. Nakahira, T. Hirano, and K. Niihara. 1995. Tensile creep behavior of alumina/silicon carbide nanocomposite. Journal of the American Ceramic Society 77(12) 3259-3262. ... 

R. Bodet, X. Bourant, J. Lamon, and R. Naslain, Tensile Creep Behavior of A Silicon-Carbide-Based Fibre with Low Oxygen Content, J. Mater. Sci., 30 (1995), 661-677. 

X. Wu and J. W. Holmes, Tensile Creep and Creep-Strain Recovery Behaviour of Silicon Carbide Fiber/Calcium Aluminosilicate Matrix Ceramic Composites, J. Am. Cerartu Soc. 76, 2695-2700 (1993). 

This superplastically deformed silicon nitride also showed substantially improved creep resistance at high temperatures, when the stress was applied along the extruding direction. For example, the creep rates of the deformed body in tensile creep tests conducted at 1200 °C was found to be about one order of magnitude lower... 

Figure 13.7 Creep asymmetry in SN 88 silicon nitride at 1350 and 1400°C depends on stress. Tensile creep rates correspond to exponential dependence on stress, while compression creep follows the power law [43],...

Figure 13.16 Phenomenological model of the cavitation processes during tensile creep deformation in silicon nitride [15, 27].

Tensile creep in silicon nitride ceramics are best described by meso-mechanical models based on the dilatation of granular solids. These models provide a rationale for the exponential dependence of creep rate on applied stress, creep asymmetry, and the role of cavitation in the creep process. Meso-mechanical models are based on the assumption that grains of silicon nitride are rigid during deformation, so that displacements between adjacent grains can only occur along the grain boundaries. 

The contribution of cavitation to tensile strain in vitreous-bonded silicon nitride exceeds 75-95%. Cavitation is the main creep mechanism in the tensile creep of silicon nitride. 

Figure 15.6 Experimental temperature-compensated strain rates versus stress plots for tensile creep of silicon nitride-based ceramics. The stress exponents n = 3 and n = 10 are...

R. Bodet X. Bourrat J. Lamon and R. Naslain, Tensile creep behavior of a silicon carbide-based fiber with a low oxygen content J. Mat Sd., 30.661-677 (1995). 

Observations of intergranular films in silicon nitride [54] show that their width decreases with decrease in RE ion radius. Viscous flow of these films contributes to the initial stage of tensile creep deformation [49]. Smaller RE ions (Lu, Er) prefer to segregate at the triple points [48]. Larger RE ions have a preference for N and remain concentrated in the IG films. Creep behaviour is thus dependent on both intergranular film and triple point viscosities. 

C.J. Casdaska, "Tensile Creep in an In-SUu Reinforced Silicon-Nitride", Jouma/q/ /he American Ceramic Society, 77(9), 2408-2418 (1994)... 

W.E. Luecke and S.M. Wiederhom, "A New Model for Tensile Creep of Silicon Nitride", Journal of the American Ceramic Society, 82(10), 2769-2778 (1999)... 

Microstructural analyses of the effect of tensile creep on both grades of GTE hot pressed silicon nitride, i.e., whisker reinforced and non-reinforced, has essentially been completed, and a paper entitled "Tensile Creep of Whisker-Reinforced Silicon Nitride" is currently in preparation. The following provides a summary description of the results. 

S.-T. Baljan, "Tensile Creep of SiC Whisker Reinforced Silicon Nitride," Proceedings of the 27th Automotive Technology Development Contractors Coordination Meeting (ATD/CCM), p-230. Dearborn, MI October 23-26, 1989, pp. 251-264. 

B. Wilshire and H. Jiang, Deformation and failure processes during tensile creep of sintered silicon carbide, Br. Ceram. Trans. 93, 213 218 (1994). 

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