WEB Highly conductive nanostructured metallic laminated composites produced via accumulative roll bonding (ARB)Tuesday (22.09.2020) 12:05 - 12:20 S: Structural Materials 1 Part of:
As miniaturization in microelectronics is ongoing, the demand for new superior highly conductive materials arises which are able to withstand higher temperatures and loads at the same or improved conductive properties. As the conductivity of materials and alloys is limited by physical nature, the improvement has to result from new composite materials.
To deal with this task we use the accumulative roll bonding process in order to produce heterogeneous laminated metallic composites, which allows to produce sheet materials with tailored properties in a wide range. We found out that nanostructured metallic laminated composites (NLMC) are a promising candidate for improving the strength, relaxation resistance, thermal stability and reducing the coefficient of linear thermal expansion (CTE) for miniaturized highly conductive applications. The procedure follows the classical ARB route of Saito  to produce the metallic laminates starting with OFHC Cu (99.99 %) sheets of 2.0 mm thickness and Nb (99.8 % - grade 1) sheets with 1.0 mm thickness at the first cycle. The stacking order applied was Cu-Nb-Cu and up to 14 ARB cycles were performed. The measurements of the electrical conductivity after 10 ARB cycles show still 73.2 %IACS while the ultimate tensile strength (UTS) reaches up to 500 MPa. Further ARB cycles lead to a decrease in conductivity (53.3 %IACS) but the UTS increases up to 760 MPa which is especially important for mechanically stressed components. Additional advances due to variation in stacking procedure e.g. stacking of three sheets at higher ARB cycles and changes in materials e.g. Cu-alloys for additional hardening effect have been made and show the variety of heterogeneous NLMCs produced by the ARB process and their advantages as promising candidates for highly conductive microelectronic applications.
 Saito Y., Tsuji N., Utsunomiya H., Sakai T. and Hong RG. (1998), Ultra-fine grained bulk aluminum produced by accumulative roll-bonding (ARB) process, Scripta Mater. 39, 1221, 10.1016/S1359-6462(98)00302-9.