Analysis of dissimilar alloy laser weld shear test data

Small laser welds of dissimilar alloys are often encountered in the hermetic packaging of high performance components in the medical, automotive, aerospace and defense industries. In many instances the mechanical properties of these dissimilar alloy welds are unknown, and hence analysis of mechanical behavior via finite element methods is effectively impossible. A number of years ago, our organization performed a series of tests which purported to measure the shear strengths of a group of high performance materials in Fe- and Ni-base systems, both as autogeneous and dissimilar laser welds employing a hub and disk test geometry. Several of the resulting datapoints were somewhat inconsistent with our nominal expectations. The work reported here employs a combination of finite element modeling of the test geometry and some new insights developed by very recent tensile tests of autogenous laser welds employing the digital image correlation technique to measure inhomogeneous strain fields to reinterpret the original test results.