Elastic and Plastic Behavior of an Ultrafine-Grained Mg Reinforced with BN Nanoparticles

Pure microcrystalline magnesium (A mu Mg) was reinforced with hexagonal boron nitride (hBN) nanoparticles and was fabricated by powder metallurgy process followed by hot extrusion. For comparison pure magnesium powder was consolidated by hot extrusion too. Both materials exhibited a significant fiber texture. Mg-hBN nanocomposites (nc) and pure Mg specimens were deformed between room temperature and 300 A degrees C under tension and compression mode. The yield strength and ultimate tensile and compression strength as well as characteristic stresses were evaluated and reported. The tensile and compressive strengths of Mg-hBN nc are quiet superior in values compared to monolithic counterpart as well as Mg alloys. The compressive yield strength of A mu Mg was recorded as 90 MPa, whereas the Mg-hBN nancomposite shows 125 MPa at 200 A degrees C. The tensile yield strength of A mu Mg was computed as 67 MPa which is quite lower as compared to Mg-hBN nanocomposite's value which was recorded as 157 MPa at 200 A degrees C. Under tensile stress the true stress-strain curves are flat in nature, whereas the stress-strain curves observed in compression at temperatures up to 100 A degrees C exhibited small local maxima at the onset of deformation followed by a significant work hardening.