Phase transformation behavior in a multipurpose dental casting gold alloy during continuous heating

Phase transformation in a multipurpose dental casting gold alloy during con tinuous heating was studied by electrical resistivity measurements, hardnes s tests, X-ray diffraction and scanning and transmission electron microscop y. The behavior can be explained by the following reaction sequences in the nodule: alpha(1)(fcc) + alpha(2)(L1(2)) --> alpha(1)(fcc) + alpha(2)(L1(2) ) + beta(L1(0)), where fcc is face centred cubic. A discontinuous precipita tion with very fine nodules contributed to the hardening and the growth pro duced the softening. This multipurpose gold alloy is characterized by the i ntroduction of a PtZn ordered phase with L1(0) structure instead of a CuAu I phase. (C) 2000 Kluwer Academic Publishers.