Copper-titanium alloys excellent in strength, conductivity and bendability, and method for producing same

Abstract

The present invention provides a titanium copper alloy excellent in strength, electrical conductivity and bendability, characterized in that it consists essentially of 1.5 to 2.3% by mass of Ti, balance Cu and inevitable impurities; said alloy having a 0.2% yield strength of 750 MPa or greater; an electrical conductivity of 17% IACS or greater; and a relationship represented by the formula:MBR / t≦0.04×YS−30,in which, YS is a 0.2% yield strength (MPa), and MBR / t is a ratio of a minimum bending radius (MBR; mm) for no cracking when said alloy is subjected to W bend test according to JIS H3130 standard along a transverse direction to a rolling direction, to a thickness (t; mm) of test piece.

Description

FIELD OF THE INVENTION [0001] The present invention relates to copper-titanium alloys excellent in strength, electrical conductivity and bendability, and to a method for producing the same. BACKGROUND OF THE INVENTION [0002] In accordance with the recent trend toward miniaturization and lightening of electronic devices, miniaturization and lightening (thinner thickness and finer pitch) of electric or electronic components such as connector and the like are ongoing. Since thinner thickness and finer pitch of connector lead to a reduction in cross section area of contact part thereof, a decrease in contact-pressure and electrical conductivity caused by the decrease of cross section area needs to be compensated for. Metal materials used for the contact part are thus required to have higher strength and electrical conductivity. In addition, metal materials used need to have good bendability as they will be subjected to a severe bending work. [0003] Recently, an increasing amount of age-...

AI Technical Summary

Benefits of technology

[0007] Therefore, it is an object of the present invention to provide a titanium copper alloy excellent in strength, conductivity and bendability.

[0009] The present inventors have discovered that the bendability deterioration in the titanium copper alloy disclosed in the aforementioned JP 2004-285408 is due to coarse Cu—Ti intermetallic compound phases precipitated in a large amount. According to the present invention, smaller amount of coarse Cu—Ti intermetallic compound phases may be precipitated by reducing Ti concentration. Moreover, titanium copper alloy has been optimized in the structure and the production process so that desired strength and bendability at the reduced Ti concentration can be achieved.

Problems solved by technology

In addition, metal materials used need to have good bendability as they will be subjected to a severe bending work.

However, the high beryllium copper alloy has such problems that it possesses toxicity and its production process is complicated and costly.

However, according to the inventors' research, the titanium copper alloy disclosed in the specification exhibited significantly deteriorated bendability.

In particular, bendability was significantly deteriorated when there existed Cu—Ti intermetallic compound phases having a diameter of greater than 2 μm.

However, no technology has achieved well-balanced improvement in all of the strength, bendability and electrical conductivity of titanium copper alloy.