“…There are many examples that show that application of shear reduces PT pressure by a factor of 2 to 10 for some PTs [6,85,90,93,95,96,97,98,99,103], including PTs to superhard phases of BN [90,95], PTs in Si and Ge [85,96], and Zr and Zr-Nb alloys [97,98]. An important point is that some of these discoveries at relatively low pressure can be scaled up using high pressure torsion [97,98,100,101,102,99,103] and ball milling [104,105,106,107,108,109,110].…”