Effect of Zr on microstructure and properties of Cu–15Cr alloy

Abstract

In order to study the effect of Zr on the microstructure and isothermal annealing performance of Cu–Cr in situ composites, Cu–15Cr and Cu–15Cr–0.24Zr alloys were prepared by means of vacuum medium frequency induction melting technology. The two kinds of test alloys with deformation of 3.79 were subjected to isothermal annealing test. The effects of Zr on the as-cast microstructure, the isothermal annealing structure and the tensile fracture morphology of Cu–15Cr alloy were studied by means of scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and transmission electron microscopy (TEM). The results show that the addition of Zr leads to the formation of homogeneous and fine CuZr intermetallic compounds, which suppresses the formation electron microscopy of eutectic Cr phase and makes the eutectic Cr content much lower than that of Cu–15Cr alloy. The recrystallization temperature of the Cu matrix is increased, and it is maintained at a fine equiaxed crystal at 400 °C. After isothermal annealing at 400 °C for 220 h, the tensile strength, electrical conductivity and elongation of the test alloy containing Zr were 720 MPa, 68% IACS and 6.7%, respectively; while the tensile strength, electrical conductivity and elongation of the test alloys without Zr were 488 MPa, 70% IACS and 12.4%, respectively.

Keywords

Cu–Cr–Zr alloy / in-situ composites / isothermal annealing / CuZr intermetallic compounds / mechanical properties

References

[1] BiL.-m, Liup, ChenX.-h, LiuX.-k, MaF.-c, LiW.. Analysis of phase in Cu–15wt.%Cr–0.24wt.% Zr alloy [J]. The Chinese Journal of Nonferrous Metals., 2013, 23(5): 1342-1348

[2] BiL.-m, LiuP., ChenX.-h, LiuX.-k, MaF.-c, LiW.. Effect of alloying and intermediate annealing on microstructure and properties of Cu-Cr deformation processed in situ composites [J]. Rare Metal and Engineering, 2013, 42(5): 1085-1090

[3] DengJ.-q, ZhangX.-q, ShangS.-z, LiuF., ZhaoZ.-x, YeY.-f. Effect of Zr addition on the microstructure and properties of Cu–10Cr in situ composites [J]. Materials and Design, 2009, 30: 4444-4449

[4] SandimH. R. Z., SandimM. J. R., BemardiH. H.. Annealing effects on the microstructure and texture of a multifilamentary Cu–Nb composite wire [J]. Scripta Materialia, 2004, 51: 1099-1104

[5] LiuJ.-b, MengL.. Phase orientation, interface structure and properties of aged Cu–6wt.%Ag [J]. Journal of Materials Science, 2008, 43: 2006-2011

[6] WangM.-h, HuangL., ChenM.-l, WangY.-l. Processing map and hot working mechanisms of Cu-Ag alloy in hot compression process [J]. Journal of Central South University of Technology, 2015, 22(3): 821-828

[7] LiuJ.-b, MengL., ZhangL.. Effect of annealing processes on microstructure, mechanical properties and conductivity of Cu–12%Ag alloy composite-reinforced by ribers [J]. Rare Metal Materials and Engineering, 2005, 34(9): 1460-1464

[8] SkaiS., SuzukiH. G.. Effect of Sn addition on the mechanical and electrical properties of Cu15%Cr in-situ composites [J]. Materials Transactions, 2012, 44(2): 232-238

[9] ZhangQ. L., ChenX. H.. Microstructure of interfaces in a Cu–15Cr–0.1Zr in situ composite [J]. Superlattices and Microstructure, 2014, 75: 54-58

[10] LiuK.-m, JiangZ.-y, ZhaoJ.-w, ZouJ., ChenZ.-b. Effect of directional solidification rate on the microstructure and properties of deformation-processed Cu–7Cr–0.1Ag in situ composites [J]. Journal of Alloys and Compounds, 2014, 612: 221-226

[11] ArgonA. S., ImJ., SafogluR.. Cavity formation from in elusions in ductile fracture [J]. Metallurgical and Materials Transactions A, 1975, 6: 825-831

[12] HuangF. X., MaJ. S., NingH. L., GengZ. T., LuC., GuoS. M.. Analysis of phases in a Cu–Cr–Zr alloy [J]. Scripta Materialia, 2003, 48: 97-102

[13] ZengJ. K., HamalinenM.. A theoretical study of the phase equilibria in the Cu–Cr–Zr system [J]. Journal of Alloys and Compounds, 1995, 220: 53-61

[14] JacobK. T., FitznerK.. The estimation of the thermodynamic properties soft ternary alloys from binary data using the shortest distance composition path [J]. Thermoehimiea Acta, 1977, 18: 197-206

[15] ZengK. J., HämäläinenM., LukasH. L.. A new thermodynamic description of the Cu–Zr system journal of phase equilibria [J]. Journal of Phase Equilibria, 1994, 15: 577-586

[16] SharmaG., RamanuanR. V., TiwariG. P.. Instability mechanisms in lamellar microstructures [J]. Acta Materialia, 2000, 48: 875-889

[17] ClineH. E.. Shape instabilities of eutectic composites at elevated temperatures [J]. Acta Metallurgica, 1971, 19: 481-490

[18] VerhoevenJ. D., DowningH. L., GibsonE. D.. The resistivity and microstructure of heavily drawn Cu–Nb alloys [J]. Journal of Applied Physics, 1989, 65: 1293-1301

[19] WenJ.-bMetal materials [M], 2011, Beijing, China Machine Press

[20] WuY.-f, WangM.-p, LiZ., XiaF.-z, XiaC.-d, LeiQ., YuH.-c. Effects of pre-aging treatment on subsequent artificial aging characteristics of Al-3.95Cu-(1.32Mg)-0.52Mn-0.11Zr alloys [J]. Journal of Central South University of Technology, 2015, 22(1): 1-7