Effect of Mischmetal Addition on Physical and Mechanical Properties of Al-Ni-Zr Melt-Spun Ribbons

In this work, the effect of mischmetal addition on the microstructural, physical and mechanical properties of rapidly solidified (Al90Ni8Zr2)((100-x))MMx (x=0-6) alloys has been studied. In this respect, various as-spun ribbons were prepared by the single-roller melt-spinning process at a quenching wheel speed of 43m/s. The results obtained showed that mischmetal had a strong effect on the control of amorphicity of the alloy during melt-spinning process. TEM and XRD results revealed the presence of two phases, nanocrystalline -Al and amorphous phase of Al90Ni8Zr2 alloy compared with those of MM-added samples with an amorphous structure. This is believed to be related to the increase in glass-forming ability due to the addition of mischmetals to the alloy. The average crystallite size obtained for MM-free sample was in the range of 30nm as confirmed by XRD and TEM data. Phase separation and formation of second phase were observed for 6at.% MM-added sample in the as-spun state. DSC results revealed that glass transition and crystallization temperatures increased with the increase in mischmetal in Al90Ni8Zr2 system. Further, it was seen that the maximum microhardness value was obtained for the 4at.% MM-added samples (4.72GPa).