Materials Synthesis by Mechanical Alloying

Magnetic transitions in disorderedGdAl2

“…7 Disorder is introduced by mechanical milling, which is a high-energy deformation process that generates defect structures ͑dislocations and vacancies͒, atomic-scale chemical disorder, and elastic strain energy through the shearing actions of ball-powder collisions. 8 Mechanical milling is distinct from mechanical alloying in that the latter combines two initially separate components, whereas mechanical milling starts with an ordered alloy that is progressively disordered.…”

Improving Hardness and Toughness of Boride Composites Based on AIMgB₁₄

“…AlN is used in as a sintering aid in many boride, nitride, and carbide ceramics and in addition is known to getter impurities, especially O, during sintering. Mechanical alloying of hBN can produce amorphous material, and the possibility of producing an amorphous boundary phase, similar to that in Veprek's work, was investigated [19,[74][75] Since TiB 2 additions were found to improve mechanical properties, composites with higher concentrations were prepared. Both hardness and toughness were found to follow a greater-than-rule-of-mixtures relationship in AlMgB 14 -TiB 2 composites when compared to single-phase AlMgB 14 and single-phase TiB 2 .…”

“…In most high-energy milling processes, there is a size limit where larger particles fracture while finer particles tend to cold weld or deform together on impact [71][72]74] propagating reactions (MSR) [78][79][80]. Many metal diborides and mixed metal diborides can be formed by MSR .…”

“…The high level of deformation induced by MA can also be used to produce an intimate mixing of immiscible phases without a reaction [74]. This can help preserve the often nanoscale grains during sintering.…”

The mechanochemical processing of aerospace metals

“…It appears that for amorphous phases to form during mechanical milling, the increase in energy of the milled powder, which is mainly due to the increased volume fraction of grain boundaries and disordering, must raise the free energy to above the level of the amorphous state [11,12].…”