Elasticity mapping of precipitates in polycrystalline materials using atomic force acoustic microscopy

We determined the isotropic indentation modulus of precipitates in cubic materials by using the indentation modulus of the matrix as a reference. This eliminates major practical difficulty of repeatedly switching between a sample and a reference for measurement of indentation modulus using atomic force acoustic microscopy. The methodology has been demonstrated for mapping the elastic stiffness of ~500 nm sized M23C6 precipitates in alloy 625 and ferritic steel with a spatial resolution of ~50 nm.