Microscopic observation and mechanical tests of CuNiCrSi/321 brazed joints

CuNiCrSi/321 and CuNiCrSi/CuNiCrSi joints of 45 mm-thick were fabricated by brazing at the temperature of 950-1050 degrees C using compression pressur e (15-20 MPa) and Cu-Mn-Ni filler (PM-17). Microscopic observation and mechanical tests of fabricated joints were perf ormed. No defects were detected in the structure of Cu/SS and Cu/Cu joints. An inc reased nickel and silicon content within the CuNiCrSi/321 brazed joint's se am was observed. The Cu/SS brazed joints fabricated at 1000-1050 degrees C, holding time of 10-15 min have quite a high strength (UTS = 500-540 MPa at 20 degrees C) wh ich makes about 0.9 of the ultimate tensile strength of CuNiCrSi alloy. Dur ing the tensile test, the specimens were basically ruptured along the braze d seam, but the fracture occurred by the ductile mechanism.