Synthesis of Nanocrystalline Ag-Cu Supersaturated Solid Solution by Mechanical Alloying

Abstract

Nanocrystalline Ag-28Cu supersaturated solid solution is prepared by mechanical alloying (MA) using a planetary ball mill. The mechanical alloyed powders are characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and differential scanning calorimeter (DSC). XRD patterns show that the main peak of Ag-28Cu supersaturated solid solution exists at about 2θ=39° when the milling time is 30h. HRTEM images show that the grain sizes of as-prepared solid solutions have distributions from 10nm to 15nm. The interplanar spacing of (111) plane for fcc Ag-28Cu supersaturated solid solution is about 2.24Å. DSC measurement result indicates that the melting temperature of Ag-28Cu supersaturated solid solution is 783.8°C. The Ag(Cu) supersaturated solid solutions are in metastable state and they will be transformed into Ag-rich phase and Cu-rich phase simultaneously by annealing at 215°C- 415°C.

Archives of Metallurgy and Materials

“…The peak positions of Cu and Ag do not differ significantly with each other, however, the shifting of the peaks is noticed. This observation indicates the formation of the Ag(Cu) solid solution [13]. The solid solution appeared after 40 h of milling at 2θ = 39.2 o .…”

Research of the Milling Time Influence on Ag-Cu Powder Particles Size Processed by Mechanical Alloying Route

“…The eutectic Ag-28 Cu alloys present high scientific interest, as recent research proved [15,16]. As L. Li et al report in their research [15], the melting point of the eutectic alloy is 783,8 0 C and the Ag-rich and Cu-rich phases of the eutectic are metastable after aging treatment; after the annealing treatment at (215...415) 0 C the eutectic becomes stable which is stated by the same researchers. Because of the high ductility of Ag-Cu system, a process control agent (PCA) is requested during the MA.…”

“…Because of the high ductility of Ag-Cu system, a process control agent (PCA) is requested during the MA. But, along Li's research, he points out the inconvenient represented by the low efficiency of the stearic acid used as PCA regarding the powder mixture (Ag + Cu) refinement [16].…”

Fabrication of Ni, Si and Mg Supersaturated Solid Solutions in Al by Mechanical Alloying

“…Previous works have shown that annealing treatment of powders after milling or high temperatures during milling inhibit the formation of SSS as it produces the precipitation of second more stable phases (Schwarz, 1995). Other studies indicate that varying other milling parameters such as the use of Process Control Agents (PCA) and controlled atmospheres impact greatly the synthesis of SSS (Li et al, 2010). There is also contradicting evidence concerning the use of Hume-Rothery rules to predict the formation of SSS for the MA process (Moumeni et al, 2006;Bansal et al, 1994).…”