Interfacial Compositions of Silver Filler Metals on Copper, Brass, and Steel.
9th Int'l Aws-wrc Brazing Conf New Orleans Weld J 57(10):303-S--310-s
The U.S. Department of the Interior, Bureau of Mines, conducted research on silver (ag) filler metals to establish criteria for the development and evaluation of substitute silverless filler metals. Metallography and x-ray microprobe scans have been used to show the interfacial phases obtained with ag filler metals on copper, brass, and steel. Wetting tests on plates of copper, brass, and steel were made using four commercial ag filler metals with a flux. Cross sections of the filler metal-base metal interface were examined to determine the reaction products. The results show that formation of interfacial compounds is dependent upon time, temperature, and composition of filler and base metals. Interfacial regions of fractured brazed joints were examined also to determine the location of the fracture. Although the compounds formed between filler and base metal may be brittle, they do not detract from the strength of ag-brazed joints.
9th Int'l. Aws-wrc Brazing Conf., New Orleans; Weld. J., V. 57, No. 10, 10/78, Pp 303-S--310-s