The mechanical properties of the Al-7075 material, which is used in important areas such as automotive, aviation and defense industry, are still being studied by researchers. In this study, the effects of different proportions of Nb additives on the microstructure and mechanical properties of the rapidly solidified Al-7075 alloy was investigated. Rapid solidification processes were carried out with a single roller melt spinner at a disk surface speed of 25 m / s. Microstructure characterization was performed by using a scanning electron microscopy (SEM) and X-ray diffraction. According to the results, the Nb additive significantly increased the micro hardness of the Al-7075 alloy. The microhardness of the sample added with 0.5% by weight of Nb is 0.9 GPa. This value is 3 times higher than the sample without Nb added. The Nb contribution has led to modification of the dimensions and shapes of both α-Al and intermetallic phases. Nb addition reduced the average grain size from 9.1 µm to 2.46 µm.

Main aim of this study is to examine change of microstructural and the mechanical properties of Al-7075 alloy depending on B content added with different proportions. Rapid solidification process used to produce the alloys was carried out with a single roll melt spinner via a wheel with a rotational speed of 25 m/s. For the microstructural characterization of the alloys, a scanning electron microscope and X-ray diffraction analyzes were used. According to obtained results, it can be said that B addition led to modification of dimensions and shapes of both α−Al and intermetallic phases occurred, it reduced average grain size from 0.45 μm to 0.34 μm in the microstructure. The B addition also led to dramatically increase in microhardness of the Al-7075 alloy. The microhardness of the alloy with 0.4 wt. % B is 0.19 GPa, this is clearly one times higher than that of the alloy without B addition. The microhardness of the alloy with 1 wt. % B is 0.21 GPa, this is also slightly higher than that of the alloy with 0.4 wt. % B.