Improvements to the Microstructure and Physical Properties of Pd-Cu-Ag Alloys

3 Ordered Cu-(35–50) at.% Pd alloys (B2-type superstructure) have a high corrosion resistance and are distinguished by possessing very low electrical resistivity r » (4–8) × 10 ohm m (1), two properties which make them of interest to researchers developing functional materials. However, wide-scale use of these alloys is hindered by their relatively poor strength properties: the yield stress of Cu-40 at.% Pd (Cu-40Pd) alloy in the ordered state is only 400 MPa. While, for example, the ordered Cu-Au alloy (L10-type superstructure), used as electrical contact material, has a yield stress, s0.2 = 800 MPa. Studies aimed at improving the functional properties of these Cu-Pd alloys have been undertaken and have resulted in the development of ternary Cu-Pd-Ni alloys with a nearly zero temperature coefficient of electrical resistivity over a wide temperature interval. Alloys Pd-Cu-Au and Pd-CuAg have also been developed and are in use; their yield stresses are in the range 900 to 1100 MPa. However the electrical resistivity of the ternary alloys is higher than that of the initial Cu-Pd binary ordered alloy. This study will deal with possible methods for strengthening Cu-40Pd alloy and will consider changes in its ordering kinetics and its mechanical and electrical properties after alloying with silver. The results obtained may help towards developing methods to improve the mechanical properties of other ordered alloys.