Mechanism of reactive sintering of MgAlB14 by pulse electric current

The reactive sintering of the hard boride AlMgB14 from the elements was investigated using the pulse electric current sintering (PECS) method. The mechanism of formation of AlMgB14 was investigated over the temperature range 600–1400 °C. The formation of AlNgB14 begins at as low a temperature as 800 °C and is essentially complete at 1325 °C. Thus the prospect of forming nanostructured AlNgB14 is not high since earlier nucleated grains continue to grow up to the maximum sintering temperature. Under optimum conditions, the products contained AlMgB14 with a ∼93 vol%, the remaining phases include spinel and impurity from milling. The product had a hardness of 26.1 GPa and a fracture toughness of 3.1 MPa m1/2.