Moiré interferometry is used for mapping elasto-plastic deformations in 63/37 solder-copper bimaterials subjected to predominantly tensile loading. A method for quantifying the fracture parameter — the J-integral — using full-field measurement of u2-displacements has been developed. A linear relationship between crack tip opening displacements (CTOD) and the J-integral is demonstrated. The crack growth resistance curve and hence crack initiation toughness JC for the bimaterial is obtained. Full-field optical information has also suggested the possibility of using a simpler method for the J-integral estimation using a single strain gage.