Development of 3Y-ZrO2/alumina functionally graded materials by two-step sintering

Reference	Presenter	Authors (Institution)	Abstract
12-010	Vera Lúcia Arantes	Arantes, V.L.(Universidade de São Paulo);	The interest for functionally graded materials (FGM) has grown up during last 2 decades owing to the possibility of developing pieces and devices with gradual variation of properties along one or more dimensions, which allows an optimum performance as a function of imposed solicitation. On the other hand, two stage sintering is a relative new sintering technique, where the shaped pieces are heated up to a relative density of 75-92% t.d., followed by a fast cooling step, up to an inferior temperature, where the piece in maintained up to the end of densification process, with development of finer microstructures, responsible for better mechanical properties. In this work, we characterized alumina-ytria-stabilized zirconia composites, with different amounts of 3Y-ZrO2, by dilatometry. After fitting thermal behavior of the distinct composites during sintering and determining temperature of maximum densification rate, co-pressed FGMs were constructed. Then pieces were sintered by pressureless traditional technique and two stage sintering, with a peak temperature of 1450°C and soaking temperature of 1350°C. Microstructure was studied by SEM and mechanical properties: microhardness and indentation toughness, in order to compare pressureless sintered FGMs at 1500°C and two stage sintered FGMs.
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