Effect Of The Melting Atmosphere On Microstructure And Properties Of Cu-Cr Alloy

Cu-Cr alloys with various component were prepared by atmosphere-melting technique in N2, Ar and vacuum conditions respectively. The upper surfaces of alloy were analyzed by XRD , and relevant thermodynamics calculations were carried out; The non-equilibrium microstructure of Cr phase in Cu-Cr alloy with various component were investigated; Mechanical and electrical properties of CuCrl.40 alloy prepared by melting in Ar atmosphere were tested; and tensile property of CuCrO.89 and CuCrl.40 alloy prepared by melting in Ar atmosphere were tested(350癈). The result showed:1. The Cr-compound on the surface of Cu-Cr alloy prepared by melting in N2 protected atmosphere was mainly C^N (76at%) , and a spot of CraOj and Cr7C3; the Cr-compound was mainly Cr7C3(35at%) in N2 protected atmosphere. The Cr-compound on the surface of Cu-Cr alloy prepared by melting in ty protected atmosphere was evidently more than in Ar protected atmosphere.2. The morphological typing of eutectic Cr of Cu-Cr alloys were sphericity and rod-shaped. With the increase of Cr content, the morphological typing of eutectic Cr were transformed from sphericity to rod-shaped. When the amount of Cr content reached 4.20wt%, eutectic Cr in rod form was primary, and some ribbon of Cr was found.3. CuCrl. 40 alloy had excellent combination property at normal temperature, which were prepared by melting in Ar protected atmosphere. After forging process, CuCrl.40 alloy had not only high- tensile strength(425MPa), but also high-IIelongation(32.7%).4. The tensile property of high-temperature (350"C) of Cu-Cr alloys, comparing with normal temperature, obviously fell. CuCrO.89 alloy and CuCrl.40 alloy's(after solution treatment and aging) tensile strength had fallen with 12.6% and 22.7% respectively. CuCrl.40 alloy's(after forging process and solution treatment and aging) tensile strength and elongation had fallen with 61.3% and 86.2% respectively.