Ag-Cd合金贝氏体相变内耗

使用低频倒扭摆测量了Ag-42.3at％Cd合金在室温至250℃范围内等温过程中内耗随时间的变化和不同升温速率下内耗与温度的关系。试验表明,Ag-Cd合金发生贝氏体相变时内耗升高是由于贝氏体相变形核过程中母相基体点阵的不稳定,内耗的升高决定于贝氏体形核率J^*与点阵局部软化区单位体积内耗值Q_s^-1的乘积。 关键词：

INTERNAL FRICTION OF Ag-Cd ALLOY IN THE BAINITIC TRANSFORMATION

The isothermal internal friction of a Ag-42.3% Cd alloy has been measured by means of a low frequency inverted torsion pendulum apparatus between room temperature and 250℃. The relation between Q^-1 and temperature with various heating and cooling rate were determined. Experimental results show that as the bainitic transformation occurs, the Q^-1 of Ag-Cd alloy increases rapidly. It may be postulated that there are regions of instability of the parent lattice in the course of nucleation process for the bainitic transformation. The increment of Q^-1_s is a function of the product of internal friction of the fraction of the lattice localized soft region per volume and the nuclea-tion rate J^* of the bainite.