54 ISSN 1063-7834, Physics of the Solid State, 2020, Vol. 62, No. 1, pp. 54–58. © Pleiades Publishing, Ltd., 2020. Effect of Pd Concentration on the Structure and Physical Properties of Ag 100 – x Pd x (x = 40, 50, and 60 at %) Alloys S. Hayat a , A. B. Ziya a , N. Ahmad b, *, and F. Bashir c a Department of Physics, Bahauddin Zakariya University, Multan, Pakistan b Department of Physics, Khwaja Fareed University of Engineering and Information Technology, Rahim Yar Khan, Punjab, Pakistan c Lahore College for Women University, Lahore, Punjab, Pakistan * e-mail: naseeb.ahmad@kfueit.edu.pk Received May 20, 2019; revised May 20, 2019; accepted May 25, 2019 Abstract—Experimental investigations have been carried out to study the effect of Pd on the structure and physical properties of binary Ag 100 – x Pd x (at x = 40, 50, 60 at %) alloys. X-ray diffraction (XRD) patterns showed that these alloys form a face-centered cubic structure of A1 type. No superlattice peaks were observed in the diffraction patterns. Differential scanning calorimetry experiments revealed no phase transition in a temperature range of 25–1100°C. Results show that the addition of Pd leads to an increase in the value of elec- trical resistivity, whereas Vickers hardness and ultimate tensile strength decrease by increasing the concentra- tion of Pd in these alloys. The results have been discussed and compared with those given in literature. Keywords: X-ray diffraction, phase transition, Vickers hardness, ultimate tensile strength DOI: 10.1134/S1063783420010126 1. INTRODUCTION The Ag–Pd alloys occupy a special place in the his- tory of alloys. Recently, interest in Ag–Pd alloys increased due to its wide range of application, e.g., biological, electrical contacts, jewelry, etc. A lot of work has been done on these alloys in recent past. Since various properties of these alloys depend on the microstructural conditions [1], information obtained from their structure plays a crucial role in the design of alloys and their subsequent heat treatment to improve their physical properties. The knowledge of structural, electrical, and mechanical properties of these alloys is of fundamental importance in many industrial appli- cations. To the best of our knowledge, the structure, hardness, and mechanical properties of Ag 40 Pd 60 , Ag 50 Pd 50 , and Ag 60 Pd 40 alloys have not been under- stood in detail yet. The present work on Ag 40 Pd 60 , Ag 50 Pd 50 , and Ag 60 Pd 40 alloys was undertaken to inves- tigate the structure, the lattice parameters, electrical resistivity, hardness, and mechanical properties, using X-ray diffraction, differential scanning calorimetry, tensile testing, and electrical resistivity measurements. The results have been discussed and compared with those given in literature. 2. EXPERIMENTAL The alloy samples were provided gratefully by Degussa (Germany). The provided compositions of the alloys were nearly Ag 60 Pd 40 , Ag 50 Pd 50 , and Ag 40 Pd 60 . The samples were cold-rolled to prepare foils of the required thickness. These foil samples were heated at 800°C for one week under vacuum and then furnace-cooled to room temperature to obtain equilib- rium structure. The samples were polished to achieve mirror surfaces suitable for X-ray diffraction work. The XRD experiments were performed with the Shimadzu XD-5A diffractometer equipped with CuK α source, Ni filter, scintillation counter detector, and a goniometer VB-108R. The resolution of the detector was better than 1 μs. The working conditions were 45 kV and 40 mA for the X-ray tube, a counting time of 1 s per step and angular range of 2θ from 30° to 120°. The crystal structure was determined by following the standard procedure outlined in [2]. The data were first checked for any spurious peaks due to improper filtration or tungsten contamination. The Bragg angles were then determined by the use of diffraction soft- ware. The indexation of various diffraction peaks was then carried out. The values of Miller indices and lat- tice parameters were determined for each reflection. The true value of lattice parameter was then deter- mined by extrapolation of lattice parameter against the Nelson–Riley function [3]. The thermal analysis was performed with differen- tial scanning calorimeter TA instrument model Q600, USA, equipped with bifilar wound furnace, horizontal purge gas system, dual beam horizontal balance, and METALS