Abstract
Zirconia toughened alumina (ZTA) is a promising advanced ceramic material for a wide range of applications that are subjected to dynamic loading. Therefore, the investigation of dynamic compressive strength, fracture toughness and hardness is essential for ZTA ceramics. However, the relationship between these mechanical properties in ZTA has not yet been established. An example of this relationship is demonstrated using ZTA samples added with MgO prepared through conventional sintering. The microstructure and mechanical properties of ZTA composites were characterized. The hardness of ZTA composites increased for ≤0.7 wt.% MgO due to the pinning effect of MgO and decrease of the porosity in the microstructure. Oppositely, the fracture toughness of ZTA composites continuously decreased due to the size reduction of Al2O3 grains. This is the main reason of deteriorate of dynamic compressive strength more than 0.2 wt.% of MgO addition. Therefore, the SHPB test shows the improvement of the dynamic compressive strength only up to a tiny amount (0.2 wt.% of MgO addition) into ZTA ceramics.
Highlights
Advanced ceramics materials are utilized in many applications such as cutting inserts [1,2,3,4], electrical applications [5] and armor [6,7,8,9] based on their specific properties such as excellent strength, high hardness, good wear resistance and chemical stability [10,11,12]
Spinel was formed with addition more addition of MgO with denser Zirconia toughened alumina (ZTA) samples
The combination effect of these features was reflected in the positive effect on the hardness improvement while decreasing the fracture toughness of ZTA ceramics
Summary
Advanced ceramics materials are utilized in many applications such as cutting inserts [1,2,3,4], electrical applications [5] and armor [6,7,8,9] based on their specific properties such as excellent strength, high hardness, good wear resistance and chemical stability [10,11,12]. Chen et al [30] carried out the dynamic Brazilian test for Al2 O3 sample and coupled it to the digital image correlation to conduct a full-field deformation analysis of the specimens They found that the dynamic behavior of ceramics was significantly influenced by microstructural characteristics; including phase morphology, grain size and shape, composition and texture. ZTA has a comparable high hardness combined with a relatively fair fracture toughness [33] It can be a promising candidate for applications that are subjected to dynamic loading. In this regard, it was postulated that addition of MgO into Al2 O3 -based ceramics reduces the sintering temperature and grain size [39]. The current work is presented to fill this gap by discussing the mechanical properties such as hardness and fracture toughness of ZTA added with MgO, and their relationship with the dynamic strength and with the dynamic strength was examined
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