Preparation of toughened yttrium oxide ceramics from alumina whisker by binder jetting

In order to improve the fracture toughness of Y₂O₃ ceramics and realize the preparation of complex structures， Al₂O₃ whiskers （Al2O3w） are introduced to toughen Y₂O₃ ceramics， and Al2O3w/Y₂O₃ complex ceramic parts are successfully prepared by binder jetting method. The effects of Al2O3w content （1%， 3%， 5%，mass fraction，the same below） on the properties of green body forming， sintering densification， and mechanical properties are systematically investigated. The results show that the addition of Al2O3w has a little effect on the porosity of the green body， but significantly optimizes the sintering process. When the content of Al2O3w is 3%， the porosity of the sintered ceramics is as low as 57.47%， the flexural strength is enhanced to 6.54 MPa. The fracture toughness reaches 2.31 MPa·m1/2， which is 2.9 times higher than that of pure Y₂O₃. Excessive addition （5%） results in a rise in porosity to 59.47% and a decrease in fracture toughness to 1.54 MPa·m1/2. Microanalysis shows that Al2O3w inhibits crack propagation through the whisker-bridging and crack-deflection mechanism， with an optimal doping amount of 3%.