Phase and Microstructure Analysis of Cu-Cr-Zr Alloys

Phases of Cu-（0.4%-2.0%） Cr-（0.05%-0.16%） Zr alloys were analyzed in both as cast and deformed state. Solute-rich clusters of Cr, which was supposed to form during aging treatment, were observed in as cast state; along with the morphology character, corresponding preferential orientation of Cr phase in as cast state was also investigated. Precipitates were observed to distribute in the matrix with a bimodal distribution, viz. coarse precipitates with dimension larger than several hundred nanometers and fine precipitates with size of 2- 10 nm. Three types of intermetallics, the common compound of Cu51Zr14, correspondingly infrequent Cu5Zr and rare Cu5Zr3, were characterized in different samples.

Texture of deformed Cu-Cr-Zr alloys

The influences of plastic deformation, aging treatment, and alloying elements on the texture of Cu-Cr-Zr alloys were ex- plored. The texture component and intensity of Cu-Cr-Zr alloys under various working conditions after aging treatment were characterized using the orientation distributing function （ODF）. The influence of Zr content on the texture of Cu-Cr-Zr alloys was also analyzed. The reduction pass and deformation level were primary factors influencing the texture. Rolling texture appeared in a rolled plate and the fibrous textures of {111} and {001} were detected after 80% deformation. Fibrous texture with a main constituent of {111} improved the tensile strength of the alloy wire. The texture contents of {110}〈331〉 and {110}〈112〉 were predominated, whereas, those of {113}〈332〉 and {112}〈111〉 were in the minority in the Cu-Cr-Zr alloy with a higher Zr content （〉0.5wt%）. However, in the samples with a lower Zr content （〈0.1wt%）, the texture contents of {113}〈332〉, {112}〈111〉, and {111}〈110〉 were in the majority.

Effects of strain rates on dynamic deformation behavior of Cu-20Ag alloy

Copper alloy is widely used in high-speed railway,aerospace and other fields due to its excellent electrical conductivity and mechanical properties.High speed deformation and dynamic loading under impact load is a complex service condition,which widely exists in the field of national defense,military and industrial application.Therefore,the dynamic deformation behavior of the Cu-20Ag alloy was investigated by Split Hopkinson Pressure Bar(SHPB)with the strain rates of 1000-25000 s^(-1),high-speed hydraulic servo material testing machine with the strain rates of 1-500 s^(-1).The effect of strain rate on flow stress and adiabatic shear sensitivity was analyzed.The results show that the increase of strain rate will increase the flow stress and critical strain,that is to say,the increase of strain rate will reduce the adiabatic shear sensitivity of the Cu-20Ag alloy.The Cu-Ag interface has obvious orientation relationship with;(111)_(Cu)//(111)_(Ag):(^(-)111)_(Cu)//(^(-)111)_(Ag):(^(-)200)_(Cu)//(^(-)200)_(Ag) and [0^(-)11]_(Cu)//[0^(-)11]_(Ag) with the increase of strain rate.The increase of strain rate promotes the precipitation of Ag and increases the number of interfaces in the microstructure,which hinders the movement of dislocations and improves the stress and yield strength of the Cu-20Ag alloy.The concentration and distribution density of dislocations and the precipitation of Ag were the main reasons improve the flow stress and yield strength of the Cu-20Ag alloy.