Characterization of Intermetallic Compounds in Al-Cu-Bimetallic Interfaces

Intermetallic compounds (IMC) resulting from interdiffusion processes at bimetal joints or coated metals usually have worse electrical and mechanical properties compared to the pure metals (e.g. higher specific electric resistance, high brittleness). For a better understanding of the aging of Al-Cu bimetallic joints by interdiffusion, an extensive characterization of the IMC's physical properties is necessary. For that purpose, phase-pure samples of three phases (AlCu, Al2Cu and Al4Cu9) have been prepared by different processes such as physical vapor deposition or electrochemical deposition. The transition from ductile to brittle behavior complicates the mechanical handling of the samples and some phases could not be prepared in pure form, yet. By adjusting and optimizing the manufacturing processes and the development of a suitable experimental setup, first results for the characterization of IMC's electrical properties were obtained. Established values for the specific electric resistance of the phase AlCu could not be confirmed. In a further step, the so far poorly studied temperature coefficient of resistivity of each IMP will be determined.