Mechanical Properties of Brazed Joint (1)

Static Torsional Deformation at Butt Joint

Abstract

The torsional deformation mechanism at brazed joints was investigated in detail. Butt joints of two types of carbon steel brazed with pure copper were used in torsion test. The torsional deformation at filler metal was measured with optical microscope.
It was cleared from test results that the discontinuity of shear strain existed at the brazed joint. This discontinuity depends on the mechanical properties of the base and the filler metals, and joint design. Furthermore, the deformation mechanism of the filler metal was discussed in the dislocation theory. It is not expected under shear stress that the triaxial stress as under tention takes place in the filler metal of the brazed joint. Therefore, the brazed joint in torsion is strengthened by the effect of interface between base and filler metals, such as the effect of grain boundaries in the case of plastic deformation of polycrystalline metals.
Consequentry, it is suggested that the local deformation of filler metal has remarcable effect on the joint strength under dynamic loading.