Preparation and characterization of aluminium based composites reinforced with BN, B and Li3N particles
In the XIXth century, people started exploiting aluminium, which is the most common metal in the earth’s crust. Aluminium is widely used in aerospace, aeronautics, and automotive industries due to its light weight and excellent corrosion resistance. Addition of various reinforcing agents can significantly improve mechanical properties of Al-based composites.
In our previous work , we have utilized BN micro-particles (BNMPs) as a reinforcing additive to the Al matrix. The formation of AlB2 and AlN phases during the sample fabrication led to significant strengthening of the composites. The highest tensile strength of 386 MPa (4.5 wt.% BNMPs) and 170 MPa (7.0 wt.% BNMPs) was achieved at room temperature and 500°C, respectively.
The purpose of this work was to increase the amount of AlB2 and AlN hard phases. To achieve this goal, Al powder was first ball-milled with B and Li3N particles and then sintered using spark plasma sintering (SPS). The microstructure of the samples was studied using scanning electron microscopy, whereas the composition was determined using EDX analysis and Raman spectroscopy. The mechanical properties of the samples were evaluated by tensile tests.
Microstructural observation of composite materials after ball milling and SPS process revealed the formation of new phases. Raman and EDX analysis confirmed the formation of AlB2 and AlN phases in the Al-B and Al-Li3N composites, respectively. The highest tensile strength, 265 MPa, recorded for the Al-B composites contained 3 wt.% B. Concerning the Al-Li3N composites, the highest tensile strength, 299 MPa, was obtained with composites containing 5 wt.% Li3N.
1. K.L. Firestein, S. Corthay, A.E. Steinman, A.T. Matveev, A.M. Kovalskii, I.V. Sukhorukova, D. Golberg, D.V. Shtansky, High-strength aluminum-based composites reinforced with BN, AlB2 and AlN particles fabricated via reactive spark plasma sintering of Al-BN powder mixtures, Materials Science and Engineering: A, Volume 681, 10 January 2017, Pages 1-9, ISSN 0921-5093