Hardening of Dental Gold-Copper Alloys
X-ray diffraction studies of several proprietary dental gold alloys demonstrated that hardening probably is a dual mechanism of precipitation and order-hardening. Lattice parameter measurements showed that the ordered structure was AuCu. In addition, it was shown that maximum hardness occurs at about 75% full order.
Ageing behaviour in a dental low-gold alloy with high copper content
Phase transformation behaviour in a dental low-gold alloy with high copper content during continuous heating was investigated by hardness tests, electrical resistivity measurements, X-ray diffraction, scanning and transmission electron microscopies. Two kinds of solution treatment conditions (at 873 K and 1073 K) followed by iced-brine quench, represented different ageing behaviours. Although subsequent anisothermal annealing produced same phase separation of face-centred cubic disordered and ordered (Cu3Au) phases in both specimens, the specimen quenched from 1073 K had already been hardened by a spinodal decomposition. © 1998 Chapman & Hall
Effects of non-uniformities on the hardening of crystals
Abstract The ease of motion of a dislocation in a crystal is influenced by changes in lattice parameter and elastic modulus. For solid solutions where such changes are gradual the hardening is negligible, but for abrupt changes, such as occur at a precipitate, the effect is important. The changes in lattice parameter lead to the production of interface dislocations and suggest a work hardening model for one class of precipitation hardened alloys. Interface dislocations may also affect flow near a free surface.