Search

With the Chinese hospitality industry's continuous emphasis on environmental sustainability and meeting customers' needs for eco-friendly services, how to motivate employees to implement green service innovative behaviors has become an important topic in the hospitality sector. Based on self-determination theory, this study investigates the motivational path that green inclusive leadership affects hospitality employees' green service innovation behavior through the satisfaction of basic psychological needs and further verifies the moderating effect of employees' traditionality in the Chinese hospitality context. Using a three-wave longitudinal design, we collected data from 367 full-time hospitality employees in 11 Chinese hotels. The results demonstrated that green inclusive leadership is positively associated with green service innovative behavior, mediated by the satisfaction of their basic psychological needs. Additionally, we confirmed that employee traditionality weakened the impact of green inclusive leadership on hospitality employees' green service innovative behavior through basic psychological needs satisfaction (at least for the satisfaction of autonomy and competence needs). • Green inclusive leadership positively associated with employees' green service innovative behavior. • Basic psychological needs mediates the effect of green inclusive leadership on green service innovative behavior. • The strength of the mediation relies on the levels of employee traditionality. [ABSTRACT FROM AUTHOR]

Zirconia-toughened alumina ceramic particle (ZTA P)-reinforced high Cr cast Fe matrix composites (ZTA P /Fe composites) are promising advanced wear-resistant materials. However, due to wear and tear, the ceramic particles may shed from the Fe matrix because of their low interfacial bonding properties. In the present work, we investigated interfacial characteristics and abrasive wear behaviours of ZTA P /Fe composites. Results showed that sintering played a significant role in the formation of sintering necks and consequently affected both compressive strengths and porosities of ZTA ceramic preforms. Optimum compressive strength (44.3 MPa) and porosity (25.2%) were obtained when sintering was performed at 1350 °C for 1 h. Subsequently, ZTA P /Fe composites without evident defects were fabricated by infiltration casting. Scanning electron microscopy, electron probe microanalysis and transmission electron microscopy were also used to analyse the microstructures and phase constituents of the interfacial layers of composites. Effects of applied wear loads on the wear behaviour evolutions and wear mechanisms of composites were examined. Wear resistances of ZTA P /Fe composites were found to be 1.64–2.21 times as compared to the Cr15 specimen. [ABSTRACT FROM AUTHOR]

We performed a first-principles calculation to investigate the 85 different Ni 3 Ti/Al 2 O 3 interfaces. The study shows that the formation of metal-oxygen interfaces and high symmetric interfacial stacking sequences is highly favored both by work of adhesion and interfacial energy. At high temperature and O-poor condition, the metal-metal interfaces show higher thermodynamic stability than metal-oxygen interfaces. The first principles tensile test predicts that the main cause of mechanical failure in Ni 3 Ti/Al 2 O 3 interface is attributed to the breaking of the Ti-Ni bonds proximity to the interface in the bulk Ni 3 Ti phase. The interfacial energies of the Ni&Ti-Al2 interfaces at 1000K are increased with the increasing of the partial pressure of oxygen, while for Ni&Ti-O interfaces which are decreasing. Image, graphical abstract [ABSTRACT FROM AUTHOR]

The preparation, microstructure and mechanical properties of ZTA particles reinforced Fe matrix composites (ZTA P /Fe composites) were systematically investigated. The X-ray diffraction (XRD), scanning electron microscopy (SEM) and electron probe microanalysis (EPMA) were used to analyze the microstructure and phase constituents, the hardness (H) , Young's modulus (E) and plasticity factor (δ A) were determined as well. The nickel-chromium double-layer coated ZTA P of core-shell structure was prepared by electroless plating and multi-arc ion plating technologies. The modified ZTA P is consisted of the α -Al 2 O 3 , t -ZrO 2 , α -Cr and γ -Ni phases. In addition, the compressive strength of ceramic preforms is high due to a compact sintering neck formed among ZTA P during high temperature sintering. The preferred sintering process for ZTA ceramic preforms is determined as 1350 °C + 1 h, in this case the preforms show the remarkable porosity and highest compressive strength which are 27.8% and 35.0 MPa, respectively. The interfacial metallurgical chemical reactions occurred during infiltration casting process, which ensure the excellent metallurgical interfacial bonding of the ZTA P /Fe composites. The interface contains double transition layers, which refer to silicate and CrFe phases, respectively. The H , E and δ A of interfacial double transition layers were measured by the nano-indentation method, the values of which are situated between the ZTA P and iron matrix. [ABSTRACT FROM AUTHOR]

To investigate the erosive wear-corrosion behavior of ZTA P ceramic reinforced high chromium cast iron matrix composites in two types of sand at various rotational speeds, the ZTA P /Fe composites were fabricated. The interface characteristics, erosion wear-corrosion and erosive wear mechanism have been investigated in a slurry condition at various erosion rotational speeds. The chemical composition of the matrix material was determined using a spark spectrometer. SEM, TEM, 3D laser scanning microscope and AFM were used to analyze the microstructure characteristics and worn surface morphology of the composites. Furthermore, the wear loss rate and relative erosive wear resistance of ZTA P /Fe composites and Cr15 standard specimen measurements were conducted. The results showed that the interface between the ZTA P ceramics and the Cr15 matrix exhibits a continuous transition layer without visible defects and close contacts. In the case of SiO 2 and SiC abrasive sand, the wear rate of ZTA P /Fe composites and Cr15 standard specimens increases with erosion time. The wear rate of ZTA P /Fe against SiO 2 sand is lower than that of against SiC sand. ZTA P /Fe composites was found to exhibit a better corrosion resistance property than that of Cr15 standard specimens. [Display omitted] • A continuous transition layer and tightly contacts without visible defects, ensuring an excellent interfacial bond. • The addition of the ZTA ceramics can improve the corrosion resistance performance of high chromium cast iron. • For SiO 2 sands, the relative erosive wear resistance of the composites reaches 1.68–2.43 times the reference Cr15matrix. • For SiO 2 sand, the erosive wear mechanism of composites is the fatigue wear and corrosion of the iron matrix. [ABSTRACT FROM AUTHOR]

• A new mechanism of Si element improving the oxidation resistance of Ti-based materials was revealed via short-term oxidation process. • Si element was beneficial for increasing the activation energy of oxidizing and decreasing the oxidation rate of composites. • The oxidation resistance of (Ti 5 Si 3 + TiC)/Ti6Al4V composites was increased with the increase of dissolved Si element content. Initial oxidation behaviors of (Ti 5 Si 3 + TiC)/Ti6Al4V composites were investigated using the simultaneous thermal analyzer in air for 2 h at 700 °C, 750 °C and 800 °C, respectively. Composites had a higher effective activation energy of oxidizing and lower oxidation rate than Ti6Al4V alloy, revealing that the composites possessed the higher oxidation resistance. The improvement of oxidation resistance of composites derived from the dissolved Si element in matrix and was strengthened with the content of dissolved Si increasing. Ti 5 Si 3 and TiC particles showed a minor influence on the oxidation behaviors of composites. [ABSTRACT FROM AUTHOR]

• The oxidation resistance of (Ti5Si3 + TiC)/Ti6Al4V composites was improved obviously by the Si element. • Si element availed the densification of oxide scale to decrease the O element concentration in the oxide scale. • The densification of oxide scale was beneficial for eliminating the spallation of oxide scale. This study focused on the objective to reveal the effect of Si element on the oxidation behaviors of (Ti 5 Si 3 + TiC)/Ti6Al4V composites. The oxidation testing at 700 °C and 800 °C for 100 h, respectively, indicated that the oxidation resistance of (Ti 5 Si 3 + TiC)/Ti6Al4V composites were improved obviously. The two aspects contributed to the improvement: 1) the oxide scale was densified owing to that the SiO 2 sealed the voids among TiO 2 scale; 2) with the densification, the oxide scale of composites bonded well with the substrate. The oxidation behaviors of composites were hardly affected by TiC particles. [ABSTRACT FROM AUTHOR]

To improve the strength and toughness of Mg matrix composites, we propose a novel strategy to successfully develop Mg matrix composites reinforced with alternating fiber-like nanoparticle-rich (NPR) zones. A combination of in-situ casting and hot thermomechanical processing approach is employed to achieve this unique microstructure, and the influence of spatial arrangement of TiB 2 nanoparticles on the microstructure, mechanical behavior, strengthening and toughening mechanisms are investigated in detail. The results show that the designed nanocomposite exhibits alternative fiber-like NPR zones and nanoparticle-free (NPF) zones, leading to the typical bimodal structure. Meanwhile, EBSD analyses reveal that the fiber-like NPR zones have much higher density of geometrically necessary dislocations than NPF zones. Accordingly, the hardness and elastic modulus in fiber-like NPR zones are enhanced significantly, acting as "hard" units, while NPF zones with high plasticity factor acting as "soft" regions. As a consequence, superior combination of tensile strength (388 MPa) and ductility (10.1%) is realized in TiB 2 /AZ91 nanocomposite when compared to AZ91 matrix. The strengthening mechanisms of the nanocomposite are evaluated quantitatively, and found that the fiber-like arrays significantly enhanced the load-bearing capacity of TiB 2 nanoparticles. Moreover, grains in NPF zones can deform easily, acting as strain bearing soft units, coupling with cracks deflection caused by the "hard" NPR zones, both of which are responsible for toughening nanocomposite. Image 1 • Mg matrix composite reinforced with specific spatial arrangement of TiB 2 nanoparticles is developed. • Designed nanocomposite consists of alternative fiber-like NPR and NPF zones. • Superior combination of tensile strength (388 MPa) and ductility (10.1%) is realized. • The "hard" NPR and "soft" NPF zones are responsible for strengthening and toughening nanocomposite, respectively. [ABSTRACT FROM AUTHOR]

BaO and TiO 2 reacted and produced BaTiO 3 in the process of sintering. As a result, the diffraction peaks of BaTiO 3 became stronger with the increasing BaO/TiO 2 contents. The diffraction peaks of NiAl shifted smaller angle to left with the addition of BaO/TiO 2. Meanwhile, the lattice distortion obviously occurred in the composite structure. The composites with the addition of BaO/TiO 2 presented high microhardness and yield strength as well. The composite with 20% BaO/TiO 2 had the highest microhardness value and yield strength of 474.5 HV and 2786 MPa, respectively. The friction coefficient and wear rate of the composites decreased with the addition of BaO/TiO 2 and the NiAl-30% BaO/TiO 2 composite had the lowest friction coefficient at 800 °C test temperature. The BaTiO 3 was decomposed to BaO and TiO 2 during high temperature sliding. • The BaO and TiO 2 react and produce the BaTiO 3 in the process of sintering. • NiAl diffraction peaks shift smaller angle to left with the addition of BaO/TiO 2. • The composites with BaO/TiO 2 present high microhardness and yield strength. • The composites with BaO/TiO 2 display excellent tribological property at 800 °C. • The BaTiO 3 is decomposed to BaO and TiO 2 during high temperature sliding. [ABSTRACT FROM AUTHOR]

The work of adhesion (W ad), interfacial fracture toughness ( K I c int ), and electronic structure of the Fe(100)//MCs(100) (M = Ti and V) interfaces have been investigated by means of first-principles calculations. Considering two types of interfaces (type 1 and 2), two MCs (TiC and VC) and three different atomic stacking sequences (Fe-on-M, Fe-on-C and Bridge), totally twelve candidate interfacial configurations were analyzed. It is found that the W ad decreases with the order of Fe-on-C > Bridge > Fe-on-M. With the larger W ad , the type 2 Fe//MCs interfaces are more stable than type 1 Fe//MCs interfaces, in which the Fe-on-C site for type 2 Fe//VC interfaces belongs to the most stable interfacial configuration. Based on the Griffith's theory, the mechanical failure of both type 1 and type 2 Fe//TiC interfaces are more inclined to initiate at the interface. While for the Fe-on-C and Bridge site of both type 1 and type 2 Fe//VC interfaces, the mechanical failure will occur at the VC bulk phases rather than at the interface. Besides, the interfacial fracture toughness of Fe-on-C site for the type 2 Fe//VC structure is the best. The interfacial bonding character of Fe-on-C site for both Fe//TiC and Fe//VC interfaces have been investigated based on the electronic density of states and charge density difference. A mixed covalent/ionic/metallic bonding is revealed between iron and transition metal carbides. Further analysis of mulliken population and magnetic moment of interfacial atoms indicates that the Fe//VC interfaces show higher bonding strength than Fe//TiC interfaces. The high electronic density between interfacial Fe and C atoms indicates the formation of the strong interfacial covalent Fe–C bonds, where Fe//VC interfaces exhibit stronger interfacial bonding than Fe//TiC interfaces. Image 1 • Fe//MCs interfaces were studied to reveal their adhesion strength, fracture mechanism and interfacial bonding. • The interfacial bonding strength of the Fe-on-C site for the type 2 Fe//VC interface is the highest. • The mechanical failure of Fe//TiC interfaces is inclined to initiate at the interface rather than the bulk sides. • Fe//VC interfaces are predicted to fail at the VC bulk side rather than at the interface. [ABSTRACT FROM AUTHOR]

NiTi//Al 2 O 3 composites have many advantages such as large elasticity, superior hardness and wear resistance. But there is little information available about the novel adhesion strength, fracture mechanism and interfacial bonding of NiTi//Al 2 O 3 composites at the atomic scale. Therefore, the work of adhesion (W ad), interfacial energy (γ) and electronic structure of NiTi(111)//α-Al 2 O 3 (0001) interfaces have been calculated using first-principles calculations. For the models with the same stacking site, O-terminated interfaces have larger W ad and smaller γ than Al-terminated interfaces. For the models with same termination, the stability of Ni(Ti)-Al interfaces decreases with the order of HCP > MT > OT, while the stability of Ni(Ti)-O interfaces decreases as MT > HCP > OT. The Ti-O-MT interface belongs to the most stable interfacial configuration with the smallest interface energy among all studied interfaces. Using Griffith's theory, it is predicted that the mechanical failure of NiTi//α-Al 2 O 3 interfaces are inclined to initiate in the interior of NiTi bulk or at the interface rather than Al 2 O 3 side in most cases. Furthermore, density of states and electron density difference analysis indicate that the dominant interfacial adhesion mechanism for the Ni Al interfaces is the formation of mainly metallic Ti Al and Ni Al bonds, while the Ti O interface exhibits mixed covalent/ionic character with higher interfacial binding strength. The interface energies of Ni-Al 2 -HCP2 and Ti-Al 2 -HCP2 configurations at 298 K are increased with the increasing of the partial pressure of oxygen, indicating their thermodynamic stabilities are decreased in the oxygen rich condition. Meanwhile, the Ni-O-MT and Ti-O-MT interfaces are stabilized by increasing the partial pressure of oxygen. Unlabelled Image • NiTi//α-Al 2 O 3 interfaces were studied to reveal their adhesion strength, fracture mechanism and interfacial bonding. • Ti-O-MT interface is the most stable interfacial configuration with the smallest interface energy of 2.07 J/m2. • The mechanical failure are inclined to initiate in the interior of NiTi bulk rather than the interface. [ABSTRACT FROM AUTHOR]

• The initial oxidation temperature of Ti(C,N) powder was declined with doping by Fe, Cr and W. • As the rim of TiO 2 transformed to a p-type semiconductor, Fe3+ cations prefer to diffuse through the core of TiO 2. • The oxidation behavior was dominated by diffusion process. • A mix oxidation model was proposed to describe the oxidation process of composites. In this work, Ti(C,N)-304ss cermets with TiB 2 /WC were fabricated by powder metallurgy technique and their oxidation behavior were studied. With TiB 2 /WC addition, the outward diffusion of Fe through TiO 2 was relieved and the oxidation resistance was improved. As metallic atoms were doped into the rim of Ti(C,N), its initial oxidation temperature was declined. Besides, a mixed oxidation model was proposed to describe the oxidation behavior of composites. Holes in TiO 2 were eliminated due to the TiB 2 /WC addition and the diffusion-control oxidation process was the main oxidation mechanism. [ABSTRACT FROM AUTHOR]