Irradiation effects cracking

Table III. Effect of Irradiation on Cracking and Adhesion of End-Sealing Compounds"...

The consequences of post-irradiation effects in polymer materials are progressive reduction in strength, cracking and embrittlement. Some reduction in these effects can be achieved by annealing of the trapped radicals, addition of appropriate... 

SiC matrix, and the number of He bubbles and cracks strongly depended on the fabrication process of SiC/SiC composites. The size of the bubbles also depended on the fabrication process of SiC/SiC composites. The turbostratic carbon structure was formed in the carbon interphase layer due to irradiation, although the interphase layer was the nongraphitic carbon structure before irradiation. Furthermore, a new crystalline SiC phase was observed in the carbon interphase irradiated with Si ions. Details of irradiation effects on SiC/SiC composites are described in Refs. [67-69]. 

Plots showing effects of irradiation on crack-arrest toughness, /C a, vs temperature for HSSI weld 73W, the same weld metal as in Fig. 10.9a (Iskander et al., 1992). 

Iskander S K, Corwin W R and Nanstad R K (1992), Effects of irradiation on crack-arrest toughness of two high-copper welds, pp. 251-269 in Effects of Radiation on Materials 15th International Symposium, ASTM STP1125, R E StoUer, A S Kumar and D S GeUes, eds, American Society for Testing and Materials, Philadelphia, PA. 

The hardness of the electron beam irradiated specimens increased from that of crack-healed specimens without electron beam irradiation in the vicinity of the sur ce. The dq>th influenced by electron beam irradiation was found to be about 2 pm. Irradiation of0.432 MGy caused a 38 % hardness increment to surface of the crack-healed specimens. A similar irradiation effect was achieved in non crack-healed specimen. The hardness in the vicinity of the surface varied with electron beam irradiation dose and the optimized conditions of electron beam irradiation to crack-healed and non crack-healed specimens were determined to be 0.432 MGy and 0.216 MGy, respectively. 

Irradiation Effects on Stress Corrosion Cracking of Stainless Steels.811... 

The yield stress due to irradiation hardening, and therefore the effective crack tip strain rate... 

Polyethylene and polystyrene are examples of plastics subject to environmental stress cracking. Crack resistance tests have shown that surfactants, alcohols, organic acids, vegetable and mineral oils, and ethers provide an active environment for stress cracking of polyethylene. Table 6 lists typical sterile devices and plastic materials used to fabricate them, while Tables 7-9 list the potential effects of sterilization processes on polymeric materials. The effect of gamma irradiation on elastomeric closures has been studied by the Parenteral Drug Association [15]. 

Deterioration was visible in all irradiated primers as color changes in expl and brass parts, corrosion of brass, and cracking of expl layers. As exposure of the production types increased, weak detonations indicating some degradation were detected while impact sensitivity was still above standard subsequent loss of charge occurred as sensitivity decreased, both effects being greatest in the No 26 primers... 

However, there could also be an alternate rationale. Belyaeva et al (Ref 49) suggest that the decompn of crystalline RDX begins at crystal defects already present or temp induced (possibly also induced by pre-irradiation). De-compn leads to deformation of the crystal lattice and more defects. If decompn products cannot diffuse, they crack the crystal which leads to a suddenly increased evolution of gas. This model can explain the memory and preirradiation effects, but is incapable of explaining... 

Complete degassing of the TiO2-100 increased the BET area from 77.3 to 97.1 sq. meters per gram (see Table IV), perhaps because of clearing of cracks or channels. The relative effect of x-irradiation was about the same, however, in that a 10 to 15% decrease occurred with both degassed and nondegassed material. 

Pronounced activity was established for the alcohols and aldehydes with one to five carbon atoms. ert-Butyl alcohol did not form ozone during the 10-hour irradiation period. The effect of substituting the hydrogen by different functional groups has been studied for ethane. The ozone-forming capacity of the resulting compounds is indicated by the total crack depth in millimeters obtained after 10 hours of irradiation. 

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