Cu 6Sn 5 is a critical intermetallic compound in soldering operations. Conventional equilibrium phase diagrams show that this compound is of either a hexagonal or monoclinic structure at temperatures above and below 186 °C, respectively. Under nonequilibrium conditions, the crystal structure is dependent on composition, temperature, and processing history. The effect of Zn, Au, and In on the hexagonal to monoclinic polymorphic transformation in Cu 6Sn 5 intermetallics is investigated using variable temperature synchrotron powder x-ray diffraction and differential scanning calorimetry. It is revealed that, as in the case of trace Ni additions, the alloying elements Zn and Au completely stabilize the hexagonal Cu 6Sn 5 and prevent the phase transformation. In contrast, In additions only partially stabilize the hexagonal Cu 6Sn 5.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering