Effects of B Addition on the Microstructure and Microhardness of Melt-Spun Al-7075 Alloy

Abstract

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.

Effect of heat treatment time on magnetic properties of NdFeB-based permanent magnetic alloys

“…Uygun üretim yönteminin seçimi, ısıl işlem, tane sınırı difüzyonu prosesi (GBDP), alaşımlama bu prosesler arasında yer almaktadır [6][7][8][9][10]. Hızlı katılaştırma yöntemlerinden birisi olan ergiyik eğirme prosesi ile oldukça yüksek soğutma hızları kullanılarak amorf ve nispeten ince tane dağılımına sahip bir mikroyapı ve sonuç olarak, üstün manyetik özelliklere ulaşmak mümkündür [11][12][13][14]. NdFeB mıknatısların manyetik özelliklerinin, ısıl işlemle birlikte modifiye edildiği bilinmektedir [15].…”