Effect of different alloy elements on the properties of melt spun Al7075 alloy

The main purpose of this study is to examine the effect of B and Nb additives added in different weight percentages on the microstructural and mechanical properties of Al-7075 alloy, which is used in important fields such as automotive, aerospace and defense industries and is still being studied by researchers. The rapid solidification process used to produce ribbon alloys was carried out with the aid of a single roller melt spinner, consisting of means of a copper disc with a rotational speed of 25 m/s. Optical microscope, scanning electron microscope and X-ray diffraction analyzes were used for the microstructural characterization of the ribbon alloys. According to the results obtained, both B and Nb additives led to a continuous decrease in the grain size of the -Al phases. With the B additive, the average grain size in the alloy changed from 0,45 m to 0,34 m. With the Nb additive, the average grain size in the alloy changed from 9,1 m to 2,46 m. In addition, with the effect of these additives, the distribution of the α-Al phases has changed from an irregular state to a equiaxed state, so that the distributions of these are more uniform. On the other hand, these additives caused changes in the sizes and shapes of second phase particles in the microstructure. With the effect of both additives, a striking increase in the microhardness of the alloy was observed. The microhardness of the alloy with 0,4 wt. % B was 0,19 GPa, which was about 2 times the microhardness of 0,10 GPa of the alloy without the B additive. Whereas the microhardness of 0,21 GPa of the alloy with 1,0 wt. % B additive showed a slight increase compared to that of the alloy with 0,4 wt. B additive. The microhardness of the alloy with 0,2 wt. % Nb additive was 0,45 GPa, which was about 5 times the microhardness of 0.10 GPa of the alloy without the B additive. The microhardness of 0.92 GPa of the alloy with 0.5 wt. % Nb additive was also about 2 times that of the alloy with 0.2 wt. % Nb additive.