Production and charactarization of Al-Si-Fe-TM (TM=B, Ni, Nb) alloys by melt- spinning process

In the present study, the effect of Ni additions on microstructure, morphology, mechanical and creep properties of the Al-Si-Fe-Nb and Al-Si-Fe-B alloys were systematically investigated. In the first part, the effect of Ni addition on the microstructure evolution and mechanical properties of conventional cast Al-20Si-9Fe-1.2Nb and Al-20Si-9Fe-1.2B alloys were investigated. Results exhibited that the as-cast microstructure of studied alloys were mainly consisted of primary Si particles, β-phase, δ-phase and α-Al matrix. Ni addition resulted in coarsening both of Si particles and Fe-bearings in case of Al-Si-Fe-Nb alloy, in contrast the microstructure of Al-Si-Fe-B alloy was significantly refined. Hardness value was improved by Ni addition, was relatively increased from 101 Hv in Al-20Si-9Fe-1.2Nb alloy to 114 Hv in Al-20Si-9Fe-1.2Nb-6Ni alloy, while it was decreased from 156.9 Hv in as cast Al-Si-Fe-B alloy to 114 Hv in as cast Al-Si-Fe-B-Ni alloy. In the second part, the above mentioned Al-alloys were further processed by melt-spinning technique, morphology and mechanical properties of resulted melt-spun Al-20Si-9Fe-1.2Nb, Al-20Si-9Fe-1.2Nb-6Ni, Al-20Si-9Fe-1.2B and Al-20Si-9Fe-1.2B-6Ni (at wt. %) ribbons were investigated in order to study the effect of Ni addition. It is observed that Ni addition increases Si solid solubility in α-Al matrix in both studied melt-spun Al-alloys. The obtained ribbons of Al-Si-Fe-Nb, Al-Si-Fe-Nb-Ni and Al-Si-Fe-B alloys were partially amorphous, while melt-spun Al-Si-Fe-B-Ni ribbons were fully amorphous. Vickers micro-hardness value has a slight increment from 206.6 Hv in Al-Si-Fe-Nb ribbons to 211.6 Hv in Al-Si-Fe-Nb-Ni ribbons, while it is drastically increased from 215 Hv in Al-Si-Fe-B ribbons to 272.2 Hv in Al-Si-Fe-B-Ni ribbons. Key Words: Al-based alloy, melt-spinning, rapid solidification, amorphous materials.