Bulk nanostructured materials from severe plastic deformation

Principles of equal-channel angular pressing as a processing tool for grain refinement

Physics and phenomenology of strain hardening: the FCC case

http://nanomechanics.mit.edu/sites/default/files/documents/Kumar_03.pdf

Mechanical behavior of nanocrystalline metals and alloys

The recent development in the field of superhard materials with Vickers hardness of ⩾40 GPa is reviewed. Two basic approaches are outlined including the intrinsic superhard materials, such as diamond, cubic boron nitride, C3N4, carbonitrides, etc. and extrinsic, nanostructured materials for which superhardness is achieved by an appropriate design of their microstructure. The theoretically predicted high hardness of C3N4 has not been experimentally documented so far. Ceramics made of cubic boron nitride prepared at high pressure and temperature find many applications whereas thin films prepared by activated deposition from the gas phase are still in the stage of fundamental development. The greatest progress has been achieved in the field of nanostructured materials including superlattices and nanocomposites where superhardness of ⩾50 GPa was reported for several systems. More recently, nc-TiN/SiNx nanocomposites with hardness of 105 GPa were prepared, reaching the hardness of diamond. The principles of de...

https://mediatum.ub.tum.de/doc/958917/file.pdf

The search for novel, superhard materials

2,106,004 1/1938 Inglee .................................. 204/300 R 2,764,540 9/1956 Farin et al. .......................... 204/1297 3,103,235 9/1963 Stringham ................................. 138/97 3,125,464 3/1964 Harmes ................................... 18/105 3,287,248 11/1966 Braithwaite ............................. 204/260 3,618,639 11/1971 Daley et al. ............................ 137/28 3,673,073 6/1972 Tobey et al. ............................ 204/226 3,804,725 4/1974 Haynes .................................... 205/104 4,080,268 3/1978 Suzuki et al. ........................... 205/131 4,120,994 10/1978 Inoue ...................................... 427/239 4,200,674 4/1980 Inoue ...................................... 427/290 4,227,986 10/1980 Loqvist et al. .......................... 204/209 4,280,882 7/1981 Hovey ....................................... 205/50

Deviations from hall-petch behaviour in as-prepared nanocrystalline nickel

Thermal stability of electroplated nanocrystalline Ni of 10 and 20 nm grain size was investigated by differential scanning calorimetry (DSC). The temperature dependence and heat release ΔH during grain growth have been determined by linear anisothermal measurements (linear heating at 10 K min −1 ). The corresponding change in microstructure has been monitored in the temperature range between 373 K and 693 K using transmission electron microscopy (TEM). The TEM and DSC studies identified three exothermic reactions: “nucleation” and abnormal grain growth (353–562 K), normal grain growth (562–593 K) and growth towards equilibrium (643–773 K). The grain growth behaviour, and the similar heat releases ΔH = 18 J g −1 , and 16 J g −1 measured for the 10 nm and 20 nm Ni nanocrystals respectively in the DSC experiments may be related to the observed sulphur segregation at grain boundaries and triple junctions.

A.M. El-Sherik

Papers

Deviations from hall-petch behaviour in as-prepared nanocrystalline nickel

Thermal stability of nanocrystalline Ni

The corrosion behaviour of nanocrystalline nickel

Synthesis, structure and properties of electroplated nanocrystalline materials

Intercrystalline hydrogen transport in nanocrystalline nickel