This example compares the softening resistance of several alloys of this invention as previously described in the aforenoted examples to commercial alloys. Alloys were air melted with charcoal cover and Durville cast to yield twelve pound ingots 15mmx10mmx4,37 mm. The casting temperature was about 1125°C to about 1150°C. The resulting ingots were homogenized at about 850-9000C for 2 hours, then rolled from 4,37 to 1 mm in seven passes with no reheating. To resolutionize the precipitated alloying elements, the strips were returned to the furnace and held at about 850-900°C for 1 hour and then water quenched. The strips were then milled to remove oxide scale and cold rolled to 0,1 mm. The cold rolled strips were then annealed for 2 hours at about 500-5750C. The material was then cold rolled to 0,01 mm, annealed to about 450-500°C for about 2 hours and then measured for electrical conductivity. The material was then finally rolled to 0.025 mm gauge for property measurments. Softening resistance was determined by annealing samples of material at 0.025 mm gauge for 1 hour at various temperatures between 300-550°C followed by measuring the respective Vickers hardness values.

Chemical composition of CuFePMg alloys

Softening curves of CuFePMg alloys

C19700 exhibits good corrosion resistance in natural atmosphere (also sea air) and industrial atmosphere. It is insensitive to stress corrosion cracking.

CuFePMg has a good relaxation stress resistance.

Stress remaining after 1000 hours of CuFePMg (C19700)

Each test piece was heated and held at 150°C for 1000 hours and the stress relaxation property of the test was evaluated according to the method of Electronics Materials manufacturers Association of Japan Standard. Specifically , one side of the test piece after heating was held, and the stress under a load 80% of the 0,2 proof stress as an initial stress was determined. This coarse dispersoids containing Mg and P having an average particle diameter exceeding the upper limit. In addition, the alloy has a markedly low electrical conductivity because of excessive P dissolved to form a solid solution and is low in strength, bendability and stress relaxation property.

Stress relaxation of CuFePMg alloys

Stress relaxation degree for CuFePMg alloy

Rheological properties and Proof stress of CuFePMg alloys with Ni, Co, Zn and Sn additions

Bendability of CuFePMg according PMX Industries INC

Typical yield strength available at a 1t 90 degree Good way bend samples 17.5 mm in width

A bending test of CuFePMg alloy sheet was performed. A test piece of 10 mm in width and 30 mm in length was taken from each sample, GOOD WAY beneding (the bending axis is perpendicular to the rolling direction) was preformed, and the presence or absence of cracking at the bending portion was visually observed under an optical microscope at a magnification of 50 times. The bendability was evaluated according to the following criteria: Good: no cracking, Fair: slight cracking, Failure: apparent cracking

Bendability of CuFePMg alloy

Bendability of CuFePMg alloy