Quartz veins in the Eastern Tonale mylonite zone (Italian Alps) were deformed in strike-slip shear. Due to the synkinematic emplacement of the Adamello Pluton, a temperature gradient between 280°C and 700°C was effected across this fault zone. The resulting dynamic recrystallization microstructures are characteristic of bulging recrystallization, subgrain rotation recrystallization and grain boundary migration recrystallization. The transitions in recrystallization mechanisms are marked by discrete changes of grain size dependence on temperature. Differential stresses are calculated from the recrystallized grain size data using paleopiezometric relationships. Deformation temperatures are obtained from metamorphic reactions in the deformed host rock. Flow stresses and deformation temperatures are used to determine the strain rate of the Tonale mylonites through integration with several published flow laws yielding an average rate of approximately 10−14s−1 to 10−12s−1. The deformation conditions of the natural fault rocks are compared and correlated with three experimental dislocation creep regimes of quartz of Hirth & Tullis. Linking the microstructures of the naturally and experimentally deformed quartz rocks, a recrystallization mechanism map is presented. This map permits the derivation of temperature and strain rate for mylonitic fault rocks once the recrystallization mechanism is known.

Dynamic recrystallization of quartz: correlation between natural and experimental conditions

/pdf/michigan-geology-a-bibliography-march-2016-oq8ytteisi.pdf

Michigan Geology: A Bibliography, March 2016

/pdf/properties-of-copper-and-copper-alloys-at-cryogenic-2exkgapaa5.pdf

Properties of copper and copper alloys at cryogenic temperatures

Spark plasma sintering (SPS) or pulsed electric current sintering (PECS) is a sintering techni‐ que utilizing uniaxial force and a pulsed (on-off) direct electrical current (DC) under low at‐ mospheric pressure to perform high speed consolidation of the powder. This direct way of heating allows the application of very high heating and cooling rates, enhancing densifica‐ tion over grain growth promoting diffusion mechanisms (see Fig. 1), allowing maintaining the intrinsic properties of nanopowders in their fully dense products.

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R.H. Oppermann

Papers

Transactions or the american institute of mining and metallurgical engineers