Impact-Strength of Brazing Filler Metals and Brazed Joints
1964 Volume 33 Issue 8 Pages 678-683
Details
1964 Volume 33 Issue 8 Pages 678-683
As to impact-strength of brazed joints, there have been a few reports. They have not explained the relation between the impact strength of filler metals and that of the joints brazed with them, and also have not proved the state of fracture in brazed joint whose base metals as copper and copper alloys were weaker than filler metals.
Authors investigated the relation between charpy impact-strength of filler metals and brazed joints using eight kinds of filler metals in Ag-P-Cu and Ag-Cu-Zn-Cd types and copper base metal. And we studied the fracture mechanism for various brazed joints, the effects of annealing for various filler metals and brazed joints and the influences of joint thickness in brazed joints for the impact strength.
The test results summarized as follows :
1) The impact-strength of filler metals in Ag-Cu-Zn-Cd type were stronger than that in Ag-P-Cu type and the impact-strength of both filler metals was improved by increase of silver contents in filler metals.
2) The impact-strength of brazed copper joints was generally less than those of filler metals and it was determined by the impact-strength of filler metals.
3) The fracture crack in impact specimens of brazed copper joints whose filler metals had higher impact-strength than base metal began from the boundary layer between filler metal and base metal. But, the fracture crack of brazed joints whose filler metals had less impact-strength than base metals began from filler metals. As a result, the absorbed energies in brazed joints had a large difference with both brazed joints.
4) After diffusion annealing, impact-strength of brazing filler metals and brazed joints became weak in Ag-P-Cu type and strong in Ag-Cu-Zn-Cd type.
5) When impact-strength of filler metals was higher than that of base metals, the thickness in brazed joints had no effect on impact-strength of brazed joints. But, when impact-strength of filler metals was weaker than that of base metals, the joint thickness gave some influences to impact-strength.
