Microstructural evolution and mechanical properties of nano-ATZ ceramics by solid solution precipitation

Yongdong Yu,Xudong Liu,Yuchen Yuan,Wanjun Yu,Hang Yin,Zhao Yin,Yongting Zheng,Xiaodong He

doi:10.1016/j.jmrt.2021.12.057

Abstract

Alumina toughened zirconia (ATZ) nanoceramics accompanied with high-strength, high-toughness and high-hardness were prepared by in-situ nanoprecipitation from using solid solution micro-powders. The submicron-sized Al2O3 (∼445 nm) and ZrO2 (∼361 nm) grains contained low-density precipitated nano-ZrO2 (∼35 nm) and nano-Y4Al2O9 (YAM, ∼87 nm) particles, respectively, making high-performance nano-ATZ ceramics with ultrafine intracrystalline nanostructure yet achieved. There was a parallel or eutectic lattice orientation relationship between the submicrocrystals and its internal nanoparticles of their crystal planes, which is very conducive to the improvement of the mechanical properties of nano-ATZ ceramics. The fracture toughness and hardness of 30wt%Al2O3/70wt%ZrO2(3 mol%Y2O3) can reach up to 5.68 ± 0.17 MPa m1/2 (single-edge V-notched beam method, SEVNB) and 16.32 ± 0.45 GPa, respectively, which are improved by ∼25% and ∼20% compared with those of 3Y-TZP ceramics. Therefore, this method can be used to prepare nano-ATZ ceramics contained ultrafine nanoparticles and uniform distribution of Al2O3 phases.

Highlights

ZrO2 ceramics are widely used because of its excellent strength and toughness due to its t-m phase transformation and fine microstructure [1,2,3]
3.1 The analysis of AZSSP Though the X-ray diffraction (XRD) analysis (Fig. 1a), most of the Al2O3 phase in the AZSSP was dissolved into ZrO2
This is because large particles of Al2O3/ZrO2 melt are ejected from the nozzle, leaving a small amount of gas remaining in the melt to form pores

Summary

Introduction

ZrO2 ceramics are widely used because of its excellent strength and toughness due to its t-m phase transformation and fine microstructure [1,2,3]. Fracture toughness of nano-ATZ ceramics is lower than that of 2Y-TZP (12.6 MPa·m1/2) and 3Y-TZP (9.3 MPa·m1/2) [2], indicating that nano-ATZ ceramics improve their hardness by sacrificing their toughness These nano-ATZ ceramics are mainly obtained by nanopowders, which have many problems such as easy agglomeration of powders, easy abnormal growth of grains during sintering and uneven distribution of Al2O3 phase. We prepared nano-ATZ ceramics containing 30 wt% Al2O3 by a new method of solid solution precipitation from micro-powders This kind of powder with high-energy state and high supersaturation was obtained by combustion synthesis assisted spray atomization at 10~50 MPa and rapid water cooling [20,21]. This method has far-reaching guiding significance for nano-ATZ ceramics

Experimental Procedure

Results and Discussion

The microstructure and mechanical properties of nano-ATZ

Conclusion