Phase Diagram Updates and Evaluations of the Al-B-Nb, Al-Cr-Pt, Al-Dy-Mo, Al-Gd-Ni, Al-Tb-V and Al-Fe-Ni-Si Systems

By virtue of their light weight, corrosion resistance, good strength and ductility, easy fabrication and favourable economics, aluminum alloys are widely used in the industry.  To get an insight into their structure-property relationships, it is essential to understand their phase diagrams, which are maps giving the relationships between phases present in the alloy as a function of temperature and composition.  In the present set of evaluations, state-of-art information on the phase diagrams of the listed systems is presented.  A brief description of the industrial relevance of each of the listed systems is given below.  The Al-B-Nb system is of special importance for Al alloys reinforced with niobium borides and in superconducting compounds such as Nb₃Al doped with boron. In the Al-Cr-Pt system, platinum alloys containing Al and Cr have microstructures similar to nickel-based superalloys used in aero-engines and are attractive materials for heat-resistant protective coatings on superalloys.  Terbium (Tb) added to high-strength Al-V alloys refines the microstructure and enhances their mechanical properties. Al-Gd-Ni alloys are known for their high hydrogen absorption capacity and are potential materials for hydrogen storage in solids for transportation applications.  The Al-Fe-Ni-Si system is of critical importance to the aluminum industry, as commercial aluminum alloys contain significant amounts of Fe, Ni and Si, either as impurities or deliberate alloying additions.

Reference to recent data on many more aluminum alloy phase diagrams can be found in the previous issues of this journal.  Professor V. Raghavan (81) has made significant contributions to the evaluation of iron and aluminum phase diagrams. He recently retired and lives in Chennai, India.