Fatigue Strength of Silver-Filler Brazed Joints in Nickel-Copper Alloys

Abstract

The fatigue strength of silver-filler brazed joints in nickel-copper alloys was studied along with tensile strength with emphasis on the influence of filler metal, base metal and joint clearance. The brazed joint with low-melting-point filler metal contained many large defects such as blow holes, and both tensile, so that its fatigue strength was low. The strength was high for high-melting-point filler metals due to a decrease in defects. However, the fatigue strength was not so high as expected from an increase in tensile strength, because the former was more sensitive to defects than the latter. Base metal with higher elastic constants constrained the deformation of filler metel, causing the fatigue strength to increase. The effect of joint clearance on the fatigue properties did not appear clearly, because the effect of defects was much more that of joint clearance.