Mechanical properties of tungsten alloys with Y2O3 and titanium additions

In this research the mechanical behaviour of pure tungsten (W) and its alloys (2 wt.% Ti���0.47 wt.% Y2O3 and 4 wt.% Ti���0.5 wt.% Y2O3) is compared. These tungsten alloys, have been obtained by powder metallurgy. The yield strength, fracture toughness and elastic modulus have been studied in the temperature interval of 25 ��C to 1000 ��C. The results have shown that the addition of Ti substantially improves the bending strength and toughness of W, but it also dramatically increases the DBTT. On the other hand, the addition of 0.5% Y2O3, is enough to improve noticeably the oxidation behaviour at the higher temperatures. The grain size, fractography and microstructure are studied in these materials. Titanium is a good grain growth inhibitor and effective precursor of liquid phase in HIP. The simultaneous presence of Y2O3 and Ti permits to obtain materials with low pores presence

Preparation and characterization of stable aqueous suspensions of up-converting Er3+/Yb3+-doped LiNbO3 nanocrystals

The preparation of LiNbO3:Er3+/Yb3+ nanocrystals and their up-conversion properties have been studied. It is demonstrated that polyethyleneimine- (PEI) assisted dispersion procedures allow obtaining stable aqueous LiNbO3:Er3+/Yb3+ powder suspensions, with average size particles well below the micron range (100���200 nm) and the isoelectric point of the suspension reaching values well above pH 7. After excitation of Yb3+ ions at a wavelength of 980 nm, the suspensions exhibit efficient, and stable, IR-to-visible (green and red) up-conversion properties, easily observed by the naked eye, very similar to those of the starting crystalline bulk material.

Comportamiento mec��nico de la aleaci��n W+1%Y2O3 en funci��n de la atm��sfera y la temperatura

Mediante ensayos de flexi��n en tres puntos se compara y eval��a el comportamiento mec��nico de la aleaci��n W- 1wt%Y2O3 con el W puro fabricados ambos mediante HIP. Se ha obtenido la tenacidad de fractura, la resistencia a flexi��n y el l��mite el��stico en atm��sfera oxidante y de vac��o en un intervalo de temperaturas comprendido entre -196 ��C, ensayos de inmersi��n en nitr��geno l��quido, y 1200 ��C. Previamente, se ha medido la densidad, la dureza mediante ensayos Vickers y el m��dulo de elasticidad din��mico de los materiales. Adem��s, la dureza y el m��dulo de elasticidad se han comparado con los obtenidos mediante ensayos instrumentados de nanoindentaci��n. Finalmente se ha realizado un peque��o estudio de las superficies de fractura de las muestras ensayadas mediante microscop��a electr��nica de barrido para poder relacionar el modo de rotura de los materiales y las propiedades mec��nicas macrosc��picas con los micromecanismos de fallo involucrados en funci��n de la temperatura.

Superplastic deformation of directionally solidified nanofibrillar Al2O3-Y3Al5O12-ZrO2 eutectics

Nanofibrillar Al2O3���Y3Al5O12���ZrO2 eutectic rods were manufactured by directional solidification from the melt at high growth rates in an inert atmosphere using the laser-heated floating zone method. Under conditions of cooperative growth, the ternary eutectic presented a homogeneous microstructure, formed by bundles of single-crystal c-oriented Al2O3 and Y3Al5O12 (YAG) whiskers of ���100 nm in width with smaller Y2O3-doped ZrO2 (YSZ) whiskers between them. Owing to the anisotropic fibrillar microstructure, Al2O3���YAG���YSZ ternary eutectics present high strength and toughness at ambient temperature while they exhibit superplastic behavior at 1600 K and above. Careful examination of the deformed samples by transmission electron microscopy did not show any evidence of dislocation activity and superplastic deformation was attributed to mass-transport by diffusion within the nanometric domains. This combination of high strength and toughness at ambient temperature together with the ability to support large deformations without failure above 1600 K is unique and shows a large potential to develop new structural materials for very high temperature structural applications.

Comportamiento mec��nico de nuevas aleaciones de wolframio en funci��n de la temperatura

La presente memoria de tesis tiene como objetivo principal la caracterizaci��n mec��nica en funci��n de la temperatura de nueve aleaciones de wolframio con contenidos diferentes en titanio, vanadio, itria y lantana. Las aleaciones estudiadas son las siguientes: W-0.5%Y2O3, W-2%Ti, W-2% Ti-0.5% Y2O3, W-4% Ti-0.5% Y2O3, W-2%V, W- 2%Vmix, W-4%V, W-1%La2O3 and W-4%V-1%La2O3. Todos ellos, adem��s del wolframio puro se fabrican mediante compresi��n isost��tica en caliente (HIP) y son suministradas por la Universidad Carlos III de Madrid. La investigaci��n se desarrolla a trav��s de un estudio sistem��tico basado en ensayos f��sicos y mec��nicos, as�� como el an��lisis post mortem de las muestras ensayadas. Para realizar dicha caracterizaci��n mec��nica se aplican diferentes ensayos mec��nicos, la mayor��a de ellos realizados en el intervalo de temperatura de 25 a 1000 �� C. Los ensayos de caracterizaci��n que se llevan a cabo son: ��� Densidad ��� Dureza Vicker ��� M��dulo de elasticidad y su evoluci��n con la temperatura ��� L��mite el��stico o resistencia a la flexi��n m��xima, y su evoluci��n con la temperatura ��� Resistencia a la fractura y su comportamiento con la temperatura. ��� An��lisis microestructural ��� An��lisis fractogr��fico ��� An��lisis de la relaci��n microestructura-comportamiento macrosc��pico. El estudio comienza con una introducci��n acerca de los sistemas en los que estos materiales son candidatos para su aplicaci��n, para comprender las condiciones a las que los materiales ser��n expuestos. En este caso, el componente que determina las condiciones es el Divertor del reactor de energ��a de fusi��n por confinamiento magn��tico. Parece obvio que su uso en los componentes del reactor de fusi��n, m��s exactamente como materiales de cara al plasma (Plasma Facing Components o PFC), hace que estas aleaciones trabajen bajo condiciones de irradiaci��n de neutrones. Adem��s, el hecho de que sean materiales nuevos hace necesario un estudio previo de las caracter��sticas b��sicas que garantice los requisitos m��nimos antes de realizar un estudio m��s complejo. Esto constituye la principal motivaci��n de la presente investigaci��n. La actual crisis energ��tica ha llevado a aunar esfuerzos en el desarrollo de nuevos materiales, t��cnicas y dispositivos para la aplicaci��n en la industria de la energ��a nuclear. El desarrollo de las t��cnicas de producci��n de aleaciones de wolframio, con un punto de fusi��n muy alto, requiere el uso de precursores de sinterizado para lograr densificaciones m��s altas y por lo tanto mejores propiedades mec��nicas. Este es el prop��sito de la adici��n de titanio y vanadio en estas aleaciones. Sin embargo, uno de los principales problemas de la utilizaci��n de wolframio como material estructural es su alta temperatura de transici��n d��ctil-fr��gil. Esta temperatura es caracter��stica de materiales met��licos con estructura c��bica centrada en el cuerpo y depende de varios factores metal��rgicos. El proceso de recristalizaci��n aumenta esta temperatura de transici��n. Los PFC tienen temperaturas muy altas de servicio, lo que facilita la recristalizaci��n del metal. Con el fin de retrasar este proceso, se dispersan part��culas insolubles en el material permitiendo temperaturas de servicio m��s altas. Hasta ahora se ha utilizado ��xidos de torio, lantano e itrio como part��culas dispersas. Para entender c��mo los contenidos en algunos elementos y part��culas de ��xido afectan a las propiedades de wolframio se estudian las aleaciones binarias de wolframio en comparaci��n con el wolframio puro. A su vez estas aleaciones binarias se utilizan como material de referencia para entender el comportamiento de las aleaciones ternarias. Dada la estrecha relaci��n entre las propiedades del material, la estructura y proceso de fabricaci��n, el estudio se completa con un an��lisis fractogr��fico y microgr��fico. El an��lisis fractogr��fico puede mostrar los mecanismos que est��n implicados en el proceso de fractura del material. Por otro lado, el estudio microgr��fico ayudar�� a entender este comportamiento a trav��s de la identificaci��n de las posibles fases presentes. La medida del tama��o de grano es una parte de la caracterizaci��n microestructural. En esta investigaci��n, la medida del tama��o de grano se llev�� a cabo por ataque qu��mico selectivo para revelar el l��mite de grano en las muestras preparadas. Posteriormente las micrograf��as fueron sometidas a tratamiento y an��lisis de im��genes. El documento termina con una discusi��n de los resultados y la compilaci��n de las conclusiones m��s importantes que se alcanzan despu��s del estudio. Actualmente, el desarrollo de nuevos materiales para aplicaci��n en los componentes de cara al plasma contin��a. El estudio de estos materiales ayudar�� a completar una base de datos de caracter��sticas que permita hacer una selecci��n de ellos m��s fiable. The main goal of this dissertation is the mechanical characterization as a function of temperature of nine tungsten alloys containing different amounts of titanium, vanadium and yttrium and lanthanum oxide. The alloys under study were the following ones: W-0.5%Y2O3, W-2%Ti, W-2% Ti-0.5% Y2O3, W-4% Ti-0.5% Y2O3, W-2%V, W- 2%Vmix, W-4%V, W-1%La2O3 and W-4%V-1%La2O3. All of them, besides pure tungsten, were manufactured using a Hot Isostatic Pressing (HIP) process and they were supplied by the Universidad Carlos III de Madrid. The research was carried out through a systematic study based on physical and mechanical tests as well as the post mortem analysis of tested samples. Diverse mechanical tests were applied to perform this characterization; most of them were conducted at temperatures in the range 25-1000 ��C. The following characterization tests were performed: ��� Density ��� Vickers hardness ��� Elastic modulus ��� Yield strength or ultimate bending strength, and their evolution with temperature ��� Fracture toughness and its temperature behavior ��� Microstructural analysis ��� Fractographical analysis ��� Microstructure-macroscopic relationship analysis This study begins with an introduction regarding the systems where these materials could be applied, in order to establish and understand their service conditions. In this case, the component that defines the conditions is the Divertor of magnetic-confinement fusion reactors. It seems obvious that their use as fusion reactor components, more exactly as plasma facing components (PFCs), makes these alloys work under conditions of neutron irradiation. In addition to this, the fact that they are novel materials demands a preliminary study of the basic characteristics which will guarantee their minimum requirements prior to a more complex study. This constitutes the motivation of the present research. The current energy crisis has driven to join forces so as to develop new materials, techniques and devices for their application in the nuclear energy industry. The development of production techniques for tungsten-based alloys, with a very high melting point, requires the use of precursors for sintering to achieve higher densifications and, accordingly, better mechanical properties. This is the purpose of the addition of titanium and vanadium to these alloys. Nevertheless, one of the main problems of using tungsten as structural material is its high ductile-brittle transition temperature. This temperature is characteristic of metallic materials with body centered cubic structure and depends on several metallurgical factors. The recrystallization process increases their transition temperature. Since PFCs have a very high service temperature, this facilitates the metal recrystallization. In order to inhibit this process, insoluble particles are dispersed in the material allowing higher service temperatures. So far, oxides of thorium, lanthanum and yttrium have been used as dispersed particles. Tungsten binary alloys are studied in comparison with pure tungsten to understand how the contents of some elements and oxide particles affect tungsten properties. In turn, these binary alloys are used as reference materials to understand the behavior of ternary alloys. Given the close relationship between the material properties, structure and manufacturing process, this research is completed with a fractographical and micrographic analysis. The fractographical analysis is aimed to show the mechanisms that are involved in the process of the material fracture. Besides, the micrographic study will help to understand this behavior through the identification of present phases. The grain size measurement is a crucial part of the microstructural characterization. In this work, the measurement of grain size was carried out by chemical selective etching to reveal the boundary grain on prepared samples. Afterwards, micrographs were subjected to both treatment and image analysis. The dissertation ends with a discussion of results and the compilation of the most important conclusions reached through this work. The development of new materials for plasma facing components application is still under study. The analysis of these materials will help to complete a database of the features that will allow a more reliable materials selection.

Mechanical characterisation of tungsten-1wt.% yttrium oxide as a function of temperature and atmosphere

This study evaluates the mechanical behaviour of an Y2O3-dispersed tungsten (W) alloy and compares it to a pure W reference material. Both materials were processed via mechanical alloying (MA) and subsequent hot isostatic pressing (HIP). We performed non-standard three-point bending (TPB) tests in both an oxidising atmosphere and vacuum across a temperature range from 77 K, obtained via immersion in liquid nitrogen, to 1473 K to determine the mechanical strength, yield strength and fracture toughness. This research aims to evaluate how the mechanical behaviour of the alloy is affected by oxides formed within the material at high temperatures, primarily from 873 K, when the materials undergo a massive thermal degradation. The results indicate that the alloy is brittle to a high temperature (1473 K) under both atmospheres and that the mechanical properties degrade significantly above 873 K. We also used Vickers microhardness tests and the dynamic modulus by impulse excitation technique (IET) to determine the elastic modulus at room temperature. Moreover, we performed nanoindentation tests to determine the effect of size on the hardness and elastic modulus; however, no significant differences were found. Additionally, we calculated the relative density of the samples to assess the porosity of the alloy. Finally, we analysed the microstructure and fracture surfaces of the tested materials via field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). In this way, the relationship between the macroscopic mechanical properties and micromechanisms of failure could be determined based on the temperature and oxides formed

Microstructural and mechanical characterization of tungsten based materials for fusion reactors

El wolframio (W) y sus aleaciones se consideran los mejores candidatos para la construcci��n del divertor en la nueva generaci��n de reactores de fusi��n nuclear. Este componente va a recibir las cargas t��rmicas m��s elevadas durante el funcionamiento del reactor ya que estar�� en contacto directo con el plasma. En los ��ltimos a��os, despu��s de un profundo an��lisis y siguiendo una estrategia de reducci��n de costes, la Organizaci��n de ITER tom�� la decisi��n de construir el divertor integramente de wolframio desde el principio. Por ello, el wolframio no s��lo actuar�� como material en contacto con el plasma (PFM), sino que tambi��n tendr��a aplicaciones estructurales. El wolframio, debido a sus excelentes propiedades termo-f��sicas, cumple todos los requerimientos para ser utilizado como PFM, sin embargo, su inherente fragilidad pone en peligro su uso estructural. Por tanto, uno de los principales objetivos de esta tesis es encontrar una aleaci��n de wolframio con menor fragilidad. Durante ��ste trabajo, se realiz�� la caracterizaci��n microstructural y mec��nica de diferentes materiales basados en wolframio. Sin embargo, ��sta tarea es un reto debido a la peque��a cantidad de material suministrado, su reducido tama��o de grano y fragilidad. Por ello, para una correcta medida de todas las propiedades f��sicas y mec��nicas se utilizaron diversas t��cnicas experimentales. Algunas de ellas se emplean habitualmente como la nanoindentaci��n o los ensayos de flexi��n en tres puntos (TPB). Sin embargo, otras fueron especificamente desarrolladas e implementadas durante el desarrollo de esta tesis como es el caso de la medida real de la tenacidad de fractura en los materiales masivos, o de las medidas in situ de la tenacidad de fractura en las l��minas delgadas de wolframio. Diversas composiciones de aleaciones de wolframio masivas (W-1% Y2O3, W-2% V-0.5% Y2O3, W-4% V-0.5% Y2O3, W-2% Ti-1% La2O3 y W-4% Ti-1% La2O3) se han estudiado y comparado con un wolframio puro producido en las mismas condiciones. Estas aleaciones, producidas por ruta pulvimetal��rgica de aleado mec��nico (MA) y compactaci��n isost��tica en caliente (HIP), fueron microstructural y mec��nicamente caracterizadas desde 77 hasta 1473 K en aire y en alto vac��o. Entre otras propiedades f��sicas y mec��nicas se midieron la dureza, el m��dulo el��stico, la resistencia a flexi��n y la tenacidad de fractura para todas las aleaciones. Finalmente se analizaron las superficies de fractura despu��s de los ensayos de TPB para relacionar los micromecanismos de fallo con el comportamiento macrosc��pico a rotura. Los resultados obtenidos mostraron un comportamiento mec��nico fr��gil en casi todo el intervalo de temperaturas y para casi todas las aleaciones sin mejor��a de la temperatura de transici��n d��ctil-fr��gil (DBTT). Con el fin de encontrar un material base wolframio con una DBTT m��s baja se realiz�� tambi��n un estudio, a��n preliminar, de l��minas delgadas de wolframio puro y wolframio dopado con 0.005wt.% potasio (K). ��stas l��minas fueron fabricadas industrialmente mediante sinterizado y laminaci��n en caliente y en fr��o y se sometieron posteriormente a un tratamiento t��rmico de recocido desde 1073 hasta 2673 K. Se ha analizado la evoluci��n de su microestructura y las propiedades mec��nicas al aumentar la temperatura de recocido. Los resultados mostraron la estabilizaci��n de los granos de wolframio con el incremento de la temperatura de recocido en las l��minas delgadas de wolframio dopado con potasio. Sin embargo, es necesario realizar estudios adicionales para entender mejor la microstructura y algunas propiedades mec��nicas de estos materiales, como la tenacidad de fractura. Tungsten (W) and tungsten-based alloys are considered to be the best candidate materials for fabricating the divertor in the next-generation nuclear fusion reactors. This component will experience the highest thermal loads during the operation of a reactor since it directly faces the plasma. In recent years, after thorough analysis that followed a strategy of cost reduction, the ITER Organization decided to built a full-tunsgten divertor before the first nuclear campaigns. Therefore, tungsten will be used not only as a plasma-facing material (PFM) but also in structural applications. Tungsten, due to its the excellent thermo-physical properties fulfils the requirements of a PFM, however, its use in structural applications is compromised due to its inherent brittleness. One of the objectives of this phD thesis is therefore, to find a material with improved brittleness behaviour. The microstructural and mechanical characterisation of different tunsgten-based materials was performed. However, this is a challenging task because of the reduced laboratory-scale size of the specimens provided, their _ne microstructure and their brittleness. Consequently, many techniques are required to ensure an accurate measurement of all the mechanical and physical properties. Some of the applied methods have been widely used such as nanoindentation or three-point bending (TPB) tests. However, other methods were specifically developed and implemented during this work such as the measurement of the real fracture toughness of bulk-tunsgten alloys or the in situ fracture toughness measurements of very thin tungsten foils. Bulk-tunsgten materials with different compositions (W-1% Y2O3, W-2% V- 0.5% Y2O3, W-4% V-0.5% Y2O3, W-2% Ti-1% La2O3 and W-4% Ti-1% La2O3) were studied and compared with pure tungsten processed under the same conditions. These alloys, produced by a powder metallurgical route of mechanical alloying (MA) and hot isostatic pressing (HIP), were microstructural and mechanically characterised from 77 to 1473 K in air and under high vacuum conditions. Hardness, elastic modulus, flexural strength and fracture toughness for all of the alloys were measured in addition to other physical and mechanical properties. Finally, the fracture surfaces after the TPB tests were analysed to correlate the micromechanisms of failure with the macroscopic behaviour. The results reveal brittle mechanical behaviour in almost the entire temperature range for the alloys and micromechanisms of failure with no improvement in the ductile-brittle transition temperature (DBTT). To continue the search of a tungsten material with lowered DBTT, a preliminary study of pure tunsgten and 0.005 wt.% potassium (K)-doped tungsten foils was also performed. These foils were industrially produced by sintering and hot and cold rolling. After that, they were annealed from 1073 to 2673 K to analyse the evolution of the microstructural and mechanical properties with increasing annealing temperature. The results revealed the stabilisation of the tungsten grains with increasing annealing temperature in the potassium-doped tungsten foil. However, additional studies need to be performed to gain a better understanding of the microstructure and mechanical properties of these materials such as fracture toughness.

Relationship between residual stresses and mechanical behavior in ceramic composites

En este trabajo, materiales de tipo al��mina/Y-TZP (ZrO2 tetragonal, estabilizada con 3 mol. % Y2O3), como sistema cer��mico popular por sus mejoradas propiedades mec��nicas en comparaci��n con las cer��micas de al��mina puras, han sido estudiados en t��rminos de propiedades mec��nicas y tensiones residuales. El novedoso m��todo de colado en cinta, consistente en el apilamiento de cintas de cer��mica verde a temperatura ambiente y el uso de bajas presiones, se ha escogido para la presente investigaci��n con el fin de poder aprovechar al m��ximo el futuro desarrollo de materiales laminados de al��mina-��xido de circonio. Se han determinado las propiedades de los materiales obtenidos por este nuevo m��todo de procesamiento compar��ndolas con las de los materiales obtenidos por ���slip casting���, con el fin de analizar si el m��todo propuesto afecta a la microestructura y, por tanto, a las propiedades mec��nicas y tensiones residuales propias de estos materiales. Para analizar la idoneidad del proceso de fabricaci��n, utilizado para evitar la presencia de discontinuidades en las intercaras entre las l��minas as�� como otros fen��menos que puedan interferir con las propiedades mec��nicas, se estudiaron materiales cer��micos con la misma composici��n en cintas. Por otra parte tambi��n se analiz�� el efecto de la adici��n de ��xido de circonio sobre la aparici��n de tensi��nes residuales en cer��micas Al2O3/Y-TZP, teniendo en cuenta su notable influencia sobre las propiedades microestructurales y mec��nicas de los materiales, as�� como el requisito de co-sinterizaci��n de capas con diferentes materiales compuestos en materiales laminados. La caracterizaci��n del material incluye la determinaci��n de la densidad, el an��lisis de la microestructura, la obtenci��n de las propiedades mec��nicas (m��dulo de elasticidad, dureza, resistencia a la flexi��n y tenacidad de fractura) as�� como de las tensiones residuales. En combinaci��n con otros m��todos de medida tradicionales, la nanoindentaci��n tambi��n se emple�� como una t��cnica adicional para la medida del m��dulo de elasticidad y de la dureza. Por otro lado, diferentes t��cnicas de difracci��n con neutrones, tanto las basadas en longitud de onda constante (CW) como en tiempo de vuelo (TOF), han sido empleadas para la medici��n fiable de la deformaci��n residual a trav��s del grosor en muestras a granel. Las tensiones residuales fueron determinadas con elevada precisi��n, aplicando adem��s m��todos de an��lisis apropiados, como por ejemplo el refinamiento de Rietveld. Las diferentes fases en cer��micas sinterizadas, especialmente las de zirconia, se examinaron con detalle mediante el an��lisis de Rietveld, teniendo en cuenta el complicado polimorfismo del ��xido de Zirconio (ZrO2) as�� como las posibles transformaciones de fase durante el proceso de fabricaci��n. Los efectos del contenido de Y-TZP en combinaci��n con el nuevo m��todo de procesamiento sobre la microestructura, el rendimiento mec��nico y las tensiones residuales de los materiales estudiados (Al2O3/Y-TZP) se resumen en el presente trabajo. Finalmente, los mecanismos de endurecimiento, especialmente los relacionados con las tensiones residuales, son igualmente discutidos. In present work, Alumina/Y-TZP (tetragonal ZrO2 stabilized with 3 mol% Y2O3) materials, as an popular ceramic system with improved mechanical properties compared with the pure alumina ceramics, have been studied in terms of mechanical properties and residual stresses. The novel tape casting method, which involved the stacking of green ceramics tapes at room temperature and using low pressures, is selected for manufacturing and investigation, in order to take full advantage of the future development of alumina-zirconia laminated materials. Features of materials obtained by the new processing method are determined and compared with those of materials obtained by conventional slip casting in a plaster mold, in order to study whether the proposed method of processing affects microstructure and thereby the mechanical properties and residual stresses characteristics of materials. To analyse the adequacy of the manufacturing process used to avoid the presence of discontinuities at the interfaces between the sheets and other phenomena that interfere with the mechanical properties, ceramic materials with the same composition in tapes were investigated. Moreover, the effect of addition of zirconia on residual stress development of Al2O3/Y-TZP ceramics were taken into investigations, considering its significantly influence on the microstructure and mechanical properties of materials as well as the requirement of co-sintering of layers with different composites in laminated materials. The characterization includes density, microstructure, mechanical properties (elastic modulus, hardness, flexure strength and fracture toughness) and residual stresses. Except of the traditional measurement methods, nanoindentation technique was also used as an additional measurement of the elastic modulus and hardness. Neutron diffraction, both the constant-wavelength (CW) and time-of-flight (TOF) neutron diffraction techniques, has been used for reliable through-thickness residual strain measurement in bulk samples. Residual stresses were precisely determined combined with appropriate analysis methods, e.g. the Rietveld refinement. The phase compositions in sintered ceramics especially the ones of zirconia were accurately examined by Rietveld analysis, considering the complex polymorph of ZrO2 and the possible phase transformation during manufacturing process. Effects of Y-TZP content and the new processing method on the microstructure, mechanical performance and residual stresses were finally summarized in present studied Al2O3/Y-TZP materials. The toughening mechanisms, especially the residual stresses related toughening, were theoretically discussed.