B6O materials with Al2O3/Y2O3 additives densified by FAST/SPS and HIP

Fully densified B6O materials with Al2O3/Y2O3 sintering additives amounts systematically varied between 0 and 15 vol.% and Al2O3/(Al2O3 + Y2O3) molar ratios of 0.05-1 were prepared by FAST/SPS and HIP at sintering temperatures between 1725 degrees C and 1900 degrees C. Their densification and microstructure were correlated with measured mechanical properties. The addition of low additive amounts in the range of 2-3 vol.% was found to increase the fracture toughness and strength from 2.0 MPa m(1/2) (SEVNB) and 420 MPa for pure B6O to about 3.0 MPa m(1/2) and 540 MPa, but it had no effect on the hardness, which remained at a high level of 30-36 GPa (HV0.4). Higher additive contents did not yield a further improvement in the toughness but resulted in a reduction in hardness and strength. (C) 2013 Elsevier Ltd. All rights reserved.

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