Liquid Phase Separation and the Aging Effect on Mechanical and Electrical Properties of Laser Rapidly Solidified Cu100−xCrx Alloys

Abstract

Duplex structure Cu-Cr alloys are widely used as contact materials. They are generally designed by increasing the Cr content for the hardness improvement, which, however, leads to the unfavorable rapid increase of the electrical resistivity. The solidification behavior of Cu 100−x Cr x (x = 4.2, 25 and 50 in wt.%) alloys prepared by laser rapid solidification is studied here, and their hardness and electrical conductivity after aging are measured. The results show that the Cu-4.2%Cr alloy has the most desirable combination of hardness and conductive properties after aging in comparison with Cu-25%Cr and Cu-50%Cr alloys. Very importantly, a 50% improvement in hardness is achieved with a simultaneous 70% reduction in electrical resistivity. The reason is mainly attributed to the liquid phase separation occurring in the Cu-4.2%Cr alloy, which introduces a large amount of well-dispersed sub-micron-scale Cr-rich particulates in the Cu-rich matrix.

The Pseudo-Eutectic Microstructure and Enhanced Properties in Laser-Cladded Hypereutectic Ti–20%Si Coatings

“…This could be due to the refinement of the microstructure. Further, the high hardness obtained for the coating was a consequence of the rapid solidification rate in laser cladding (10 3 -10 5 • C/s), which is much higher than that normally obtained in the arc melting-metal mold process (10 2 • C/s) [10,11]. Rapid solidification results in a much refined and well-distributed Ti 5 Si 3 hard phase in the eutectic microstructure.…”

Liquid Phase Separation in Ag-Co-Cr-Fe-Mn-Ni, Co Cr-Cu-Fe-Mn-Ni and Co-Cr-Cu-Fe-Mn-Ni-B High Entropy Alloys for Biomedical Application

“…Equiatomic AgCoCrFeMnNi was designed as the combination of CoCrFeMnNi [8] and Ag because of the liquid state immiscibility in the binary phase diagrams of Ag-Co [50], Ag-Cr [51], Ag-Fe [52], Ag-Mn [53], and Ag-Ni [54]. Equiatomic CoCrFeMnNiCu was designed as the combination of CoCrFeMnNi [8] and Cu because of the flat liquidus in the binary phase diagrams of Co-Cu [55], Cu-Fe [56,57], and Cr-Cu [58], the metastable liquid miscibility gap in binary Co-Cu [59] and Cu-Fe [59], and the reports of LPS in Cr-Cu alloys [60][61][62][63]. Non-equiatomic CoCrCu x FeMnNi (x = 1, 2, 3) was also designed for investigating the Cu concentration dependence of the LPS behavior in Co-Cr-Cu-Fe-Mn-Ni HEAs.…”

Spontaneous Phase Separation of Ternary Fluid Mixtures

“…More recently, it has also been shown to play fundamental roles in volcanic eruptions [3,4] and in the organisation of cellular matters, leading to the formation of the so-called biomolecular condensates or membraneless organelles [5][6][7][8]. In industry, better understanding of the phase separation process is necessary, among others, for tuning the formation of fractures in alloys in the field of metallurgy [9,10], for manipulating the structure of polymer blends which in turn affect their mechanical and electrical properties [11][12][13], and for controlling the morphology of complex emulsions for applications in drug delivery [14][15][16] and in the food industry [17][18][19].…”