Strengthening high-stacking-fault-energy metals via parallelogram nanotwins

A variety of questions remain open in the new form of nanotwins in Ni, welcome any comments! 

Twins readily form during growth or deformation in metals of low stacking-fault energy. Fabrication of high-density growth nanotwins in high stacking-fault energy materials is technically challenging. We synthesize nanotwinned Ni foils with controlled twin patterns – pulsed electrodeposition produces conventional parallel nanotwins while direct current electrodeposition generates a new pattern of nanotwins in the parallelogram form. The parallelogram nanotwins confine dislocation motion in the cage of twin boundaries and lead to a superior strengthening effect in Ni.

http://www.sciencedirect.com/science/article/pii/S1359646215002572