Mo Matrix Research Articles

Effect of ultra-high temperature treatment on the rolled pure molybdenum for nuclear thermal propulsion

Molybdenum (Mo)-based uranium dioxide (UO2) fuel is considered one of the most promising fuel forms for deep-space exploration. The rolling process has been proposed for the preparation of Mo matrix due to its excellent performance. However, there has been limited research on the ultra-high temperature stability of Mo matrix used in nuclear thermal propulsion (NTP). Therefore, in this study, annealing experiments were carried out on rolled Mo plates within a relatively wide temperature range of 1200 to 2300 °C for 1 h to investigate the effects of temperature on the phase composition, microstructure, and mechanical property. The results showed that, despite the body-centered cubic structure of the Mo plates remaining unchanged without undergoing phase transition after high-temperatures, the intensity of the crystal diffraction peaks experienced a significant increase. The preferred growth orientation shifted from the (110) direction at lower temperatures to the (200) direction at 2300 °C. The grain shape of the rolled Mo plates changed from elongated to equiaxed after annealing, and the grain size increased from the initial 1 μm to tens of microns. No discernible surface pores or fracture bubbles were observed when annealed at 1200 to 2100 °C. However, subsequent annealing at 2300 °C revealed a proliferation of polyhedral bubbles, ranging in size from tens of nanometers to several microns, distributed both in grain boundaries and within grains. Nevertheless, there is no apparent change in the density from 1200 to 2300 °C. Bright-field TEM micrographs show that after annealing at 2300 °C, the dislocation density is significantly reduced, and the dislocation shape evolves from screw dislocation to long and straight line. In addition, the Vickers hardness value of the rolled Mo plates undergoes a significant decrease, from 247.1 to 199.6 Hv, after annealing at 1200 °C. Subsequently, in the temperature range of 1200 to 2300 °C, a gradual decline in the hardness value is observed. This work will deepen our understanding of the high-temperature resistance of rolled Mo plates and provide data to support their applications in ultra-high-temperature conditions.

Formation of uranium nitride nanoparticles via mechanical alloying of uranium-molybdenum alloy fuels in gaseous nitrogen

Uranium-molybdenum (U-Mo) alloys show promise as a nuclear fuel system due to their high thermal conductivity and fuel loading capability. However, U-Mo systems are susceptible to irradiation induced swelling ultimately affecting the cladding via mechanical and chemical interactions. To address these shortcomings, this research investigated the formation of uranium mononitride (UN) nanoparticles within a 90 wt% U/ 10 wt% Mo (U-10Mo) matrix to act as a prospective defect sink for fission products at nanometric hetero-interfaces. To promote the formation of UN, U-10Mo powders were mechanically alloyed under a high purity nitrogen atmosphere. Variations of the milling process investigated included media size, duration of milling, and number of times the milling jar was re-aerated with nitrogen gas. Characterization of the fuel microstructure was completed using light element analysis, X-ray diffraction, scanning and transmission-electron microscopy, electron energy loss spectroscopy, and atom probe tomography. UN nanoparticles measuring 1–5 nm in radius were observed in the U-Mo matrix as early as 1 h into the mechanical alloying process. Milling time in excess of 10 h was found to lead to deleterious effects induced by the stainless-steel milling media.

Effects of Al2O3 and Cr2O3 on the microstructure and properties of Mo alloys prepared via vacuum sintering

The dilemma of strength and ductility of Mo alloy at ultra-high temperature (above 1300 °C) limits its application in space reactors and other high-temperature environments. Single oxide enhancement has been unable to meet these use requirements. In this research, a strategy of synergistic reinforcement of Mo alloys with nanosized Al2O3 and Cr2O3 ceramic particles was proposed. A 300−400 nm Mo alloy powder was prepared by liquid‒solid doping, and in situ self-generated nanosized oxides were obtained. The grain size of vacuum sintered Mo alloy was very fine, at only 5.3 μm, which was one tenth of the particle size of commercial Mo alloy. Al2O3 and Cr2O3 particles were distributed in the grains of the Mo matrix, which effectively prevented the growth of Mo grains during vacuum sintering and reinforced the Mo alloy. The maximum flow stress of the Mo–Al2O3–Cr2O3 alloy reached 367 MPa at 1000 °C/1 s−1, which was better than that of the single-oxide reinforcement. The ultimate tensile strength (UTS) of the Mo–Al2O3–Cr2O3 alloy was 862 MPa, which was twice that of pure Mo. The preparation process is simple and available for industrial production. Synergistic strengthening of multiple oxides will be the best strategy for strengthening refractory alloys in the future.

Dry-sliding wear characteristics of laser clad Mo matrix alloy coatings over a wide range of temperature

In order to overcome the severe wear damage of Inconel 718 as hot parts at room temperature-1000 °C, a new-type wear resistant MoNiCr matrix coating reinforced by Si was developed on the Inconel 718 alloy by laser cladding. The Si element showed the solid strengthening effect, dispersion strengthening effect and grain refinement effect, which obviously improved the tribological performance of MoNiCr matrix coating as compared with Si-free MoNiCr coating and Inconel 718 at room temperature-1000 °C. The wear rates of coating reinforced by Si were in the order of 10−6-10−5 mm3/N.m. This is due to the combined effect of the high hardness and the formation of SiO2, MoO3, Ni2SiO4, NiMoO4, etc. as well as the friction layer.

Ultrahigh-strengthened intragranular κ-Al2O3 nanoparticles dispersed Mo composite prepared via SPS sintering of core-shell Mo nanocomposite powder

Oxide dispersion strengthening (ODS) is an effective method to improve the mechanical properties of Mo-based materials. However, the mechanical properties of traditional ODS-Mo composites are always limited by the coarsening and intergranular distribution of second-phase particles. In this work, an effective nano-reinforcement dispersion strategy was developed to fabricate an ODS-Mo composite with ultrafine grain and intragranular distribution of second-phase particles. Core-shell structural Mo nanocomposite powders, with internally distributed sub-10 nm Al2O3 dispersoids, were prepared by nano atomization doping (AD) followed by a chemical vapor transport growth strategy. Then, ODS-Mo composites with ultra-fine Mo grain (below 700 nm) and high-density intragranular κ-Al2O3 (below 20 nm) nanoparticles were prepared via spark plasma sintering (SPS), in which a coherent interface between κ-Al2O3 and Mo matrix was formed. The composites present remarkably improved hardness (above 500 HV), bend strength, and compressive yield strength (above 1664 MPa) at room temperature, with a suitable strain to fracture of 27.1 %. The calculation of strengthening mechanisms indicates that the enhancement was mainly attributed to the intragranular κ-Al2O3 nanoparticles. This nano-sized reinforcement distributed within the grain can more effectively pin dislocations and achieve dispersion strengthening in ODS-Mo composites. Therefore, this strategy can efficiently construct intragranular second-phase nanoparticles and open up new avenues to fabricate high-performance ODS-Mo composites.

Effect of Ti and Zr on high temperature mechanical and thermal properties of MoCu composites

Based on the design concept of diversified alloys, the reinforcement of TZM alloys was combined in the fabrication of MoCu composites. The MoCu composites were prepared by vacuum hot press sintering under the effect of Ti, Zr elements added separately or simultaneously, and the microstructure adjustment was realized by mechanical ball milling on the pretreatment of the original alloy powder. The results show that Ti and Zr elements form metal-based solid solutions and intermetallic compounds by diffusion with Mo and Cu matrix during the sintering process. It can not only reduce the sintering activation energy of MoCu composites to improve the densification, but also improve the mechanical properties of the composites through certain solid solution strengthening and second phase strengthening. When Ti, Zr elements are added at the same time, Zr elements can enhance the β-stabilizing effect of Mo on Ti elements and improve the solid solution effect between Ti and Mo, Cu matrix, which further improves the interfacial bonding. Therefore, the 60Mo35Cu2.5Ti2.5Zr composites have the best overall performance, and their thermal properties and mechanical properties at room and high temperatures are greatly improved compared with the original 60Mo40Cu composites.

Phase interface engineering: A new route towards ultrastrong yet ductile Mo alloy

Oxide dispersion strengthened (ODS) refractory metals, represented by tungsten and molybdenum alloy, possesses many excellent properties such as high-temperature strength, outstanding thermal microstructure stability and good resistances to oxidation and corrosion. However, in traditional preparation technologies, these ex-situ oxides usually form poor oxide/matrix interface relationships and keep coarse sizes at grain boundaries (GBs), which prominently limit the improvement of alloy mechanical properties until now. In this work, we skillfully employed novel phase interface engineering to successfully construct completely coherent oxide/matrix interfaces in ODS Mo alloys through the newly formed ternary phase oxide nanoparticles or diffusion layers. Furthermore, these ODS Mo alloys are characterized by ultrafine grains, ultrafine subgrains, small and dispersed intragranular and intergranular particles. An amount of oxygen impurities can also be depleted via phase interface engineering, thus purifying Mo matrix. The phase interface engineering endows ODS Mo alloys with ultrahigh strength, excellent ductility and excellent hot machinability, which illuminates a new research direction for those ex-situ oxide dispersion strengthened alloys with excellent mechanical properties.

Efficient Sintering of Mo Matrix Composites—A Study of Temperature Dependences and the Use of the Sinter Additive Ni

Mo matrix composites (MMC) with Mo-9Si-8B inclusions were fabricated by pressure-less sintering (PLS) and spark plasma sintering (SPS) techniques at temperatures between 1200–1500 °C using 1 wt.% Ni sinter additive. The positive impact of the addition Ni addition on the sinterability and formation of a continuous Mo matrix of MMC with randomly distributed Mo3Si and Mo5SiB2 inclusions was determined. The Ni addition increased the shrinkage of MMC during PLS by almost a third. The continuous Mo matrix of MMC and a relative density of more than 98% was obtained after SPS at 1400–1500 °C. The composite with the maximum relative density of 98% showed a Vickers hardness of 482 ± 9 (HV20). The potential of using Ni-activated PLS and SPS to produce high-density MMC is shown.

Corrosion and microstructural characterization of molybdenum cermets following hydrogen exposure up to 2630K

Ceramic-metallic (cermet) fuels are a promising fuel type for space nuclear thermal propulsion (NTP). A key feasibility issue of NTP fuels is the hydrogen chemical compatibility of candidate fuels in the proposed extreme operating temperatures for NTP systems (≥2500 K). In this study, molybdenum matrix cermets containing 40–70 vol% yttria stabilized zirconia (YSZ) particles (as a surrogate for ceramic fuel particles) were produced via spark plasma sintering (SPS) and exposed to flowing hydrogen at high temperature (2000–2630 K). Both steady state and thermally cycled (4 cycles with intermediate cooling to room temperature) conditions were examined for a constant total high temperature exposure duration of 80 min. Following testing, the Mo matrix appears robust in a Mo-YSZ cermet and exhibits acceptable mass loss (<1 wt%) with a sublinear dependence on exposure time (⅓ - ¼ power) based on hydrogen testing at 2500–2630 K with thermal cycling. Moderately higher mass losses were observed for thermally cycled (4 times) vs. isothermal specimens. The subsurface Mo-YSZ interface also remains intact despite indications of debonding at the surface. Significant hydrogen attack occurs on the YSZ particle grain boundaries in the interior of the samples at 2500–2630 K.

Phase equilibrium studies of Mo-Y2O3-ZrO2-Zr at 1200 ℃ for developing Y-Zr-O complex oxide dispersion-strengthened Mo alloys

Phase equilibria of the Mo-Y2O3-ZrO2-Zr section in the Mo-Y-Zr-O system at 1200 ℃ were studied for developing nanostructured Y-Zr-O complex oxide dispersion-strengthened Mo alloys and understanding the formation behavior of oxides. The evolution of intermetallic Mo2Zr and the powder composition of this Mo alloy during mechanical alloying (MA) were revealed. The results showed that the Mo-Y2O3-Zr section was confirmed by four kinds of two-phase regions (Mo) + αY2O3 and (βZr) + αY2O3 and three-phase regions (Mo) + αY2O3 + Mo2Zr and (βZr) + αY2O3 + Mo2Zr. These three-phase equilibria were associated with the four-phase equilibria of (Mo) + αY2O3 + Mo2Zr + (αZr) with a high concentration of O in (αZr). During MA, Mo2Zr was dissolved in the Mo matrix, and the introduced excess O and ZrO2 contaminants shifted alloy composition from Mo-Y2O3-Zr to Mo-Y2O3-ZrO2. The Mo-Y2O3-ZrO2 section was characterized by six kinds of two-phase regions Mo + βZrO2, Mo + γZrO2, Mo + Zr3Y4O12, and Mo + αY2O3, three-phase regions Mo + βZrO2 + γZrO2 and Mo + γZrO2 + Zr3Y4O12. The established Mo-Y2O3-ZrO2-Zr phase diagram suggests that the presence of excess Zr and insufficient O can bring about the formation of brittle Mo2Zr and Zr phase, and the Y/Zr ratio strongly determines the type of Y-Zr-O precipitates in Mo alloys.

Improving the Electrocatalytic Performance for the Hydrogen Evolution Reaction in the Electrodeposited Ni-Based Matrix by Incorporating WS2 Nanoparticles

Ni based alloys and composites may constitute an alternative to noble metal as a catalyst for the hydrogen evolution reaction (HER) during the water electrolysis. The aim of the present study was to evaluate the electrocatalytic activity of the electrodeposited Ni-WS2 and Ni–Mo–WS2 composites. The effect of the addition of WS2 nanoparticles on the structure, surface morphology and surface composition of Ni and Ni–Mo metallic matrix was thoroughly examined. The obtained results were used to explain the catalytic performance and the HER mechanism of the studied composites. It was found that the incorporation of the WS2 nanoparticles increased the electrocatalytic activity of the Ni and Ni–Mo matrix. The highest electrocatalytic activity was found for the Ni–Mo–WS2 electrode. This was, firstly, a consequence of the quasi-amorphous structure of the composite, which increased the real surface area of the electrode. On the other hand, the intrinsic catalytic activity was enhanced by the outer oxide layer rich in Mo oxides formed on the surface of the composite electrode. The presented research is an important contribution to the design of the non-precious composite electrodes for the HER.

Strengthening the grain boundary of Mo alloy via little TiC addition

The little TiC was added into Mo alloys by facile ball milling and subsequent sintering. Interestingly, ultrafine Mo-TiC alloy (6.53 μm) possesses quasi-cleavage transgranular fracture morphology, which is differed from traditional intergranular fracture morphology of oxide-dispersion-strengthened molybdenum (ODS-Mo) alloy. The alloy interface with the lowest strength changes from Mo grain boundaries (GBs) to grain interior, hence the crack propagates along grain interior. For one thing, some C-deficient TiC (Ti8C5) can adsorb adjacent impurity oxygen at sintering stage to generate in-situ TiOx, thereby purifying Mo matrix. For another thing, coherent interfaces between TiC/TiOx particles and Mo further strengthen Mo matrix. Moreover, a lot of TiC/TiOx particles within Mo grains could efficaciously accumulate dislocations and indirectly improve GBs strength. Compared to ball-milled Mo or ODS-Mo alloy reported in literatures, the sintered Mo-TiC alloys in present work possess a high hardness (468 HV0.2), an excellent match of high strength (1287.3 MPa) and large ductility (18.1%).

Fabrication and photosensitivity analysis of MIS Schottky barrier diodes with different molar concentrations of MoO3 thin films

We made exceptionally sensitive MIS structured diodes with positive photosensitivity in this case utilizing a single-phase crystalline material. With (0.02, 0.04, 0.06 and 0.08 M) different molar concentration and an ideal substrate temperature of 500 °C, MoO3 layer thin films were effectively produced on a glass substrate using the JNSP approach. The mean crystallite size of the films was found to decrease and their associated lattice parameters improved within molar concentration. Single-phase crystalline MoO3 films with orthorhombic crystal structure were detected in XRD analysis. Through FESEM images small plate-like surface morphology was seen to be randomly distributed. When O atomswere added to the Mo matrix, it improved optical absorption and reduced Eg values, which was investigated using the UV–Vis spectrum. When there is a larger concentration of Mo, the current–voltage (I–V) characteristics show the highest dc with low Ea values. For Cu/MoO3/p-Si type diodes, it was discovered that their corresponding ideality factor (n) decreased as the light intensity of the diodes increased to 120 mW/cm2. Significant photodiodemetrics including PS increased with Mo, and in particular the MIS diode manufacturedwith its 0.08 M exhibited superior results in which a remarkable higher responsivity was measured, also contributed to the improved performance.

In-situ oxide dispersion strengthened ultrafine-grained molybdenum alloy with enhanced hardness and bending strength

The refinement of grain size and introduction of the second phase particles are the main pathways to improve the mechanical properties of Mo materials. In this work, ultrafine-grained Mo alloy with in-situ formed intragranular MoO2 particles (average particle size, 34 nm) was prepared via spark plasma sintering (SPS) of Mo nanopowder. This ultrafine-grained Mo sample possessed excellent hardness and bending strength of 464 HV1.0 and 909 MPa, respectively, which were more than twice of the traditional coarse grained Mo alloy. It was found that these intragranular MoO2 nanoparticles were converted from the oxygen on the surface of Mo nanoparticles and had a coherent relationship with Mo matrix (MoO2 (110) // Mo (102)), which can improve strength via inhibiting grain growth, pinning and storing dislocations.

Effects of oxides nanoparticles on the microstructure and properties of Mo composites prepared via SPS sintering

Simultaneous achieving the second-phase particle strengthening, high density, and fine grain is a great difficulty for designing and preparing Mo alloys. In this study, the effects of γ-Al2O3 and Y2O3 nanoparticles on the microstructures and properties of Mo composites prepared via spark plasma sintering (SPS) were systematically investigated. It was found that for pure Mo and Mo–Y2O3 powders, Mo compact with both high density and fine grain size can't be achieved. However, Mo-Al2O3 composite with both a relatively high density (98%) and a fine grain size (1.67 μm) was synthesized successfully. The small γ-Al2O3 particles transformed into larger κ-Al2O3 particles by obvious grain boundary migration and grain growth in the sintering process, which effectively pinned the migration of Mo grain boundary with few effects on the surface atom diffusion of Mo. Moreover, there was a crystallographic orientation relationship between the κ-Al2O3 particles and Mo matrix (Mo (110)//Al2O3 (134‾1)). Ultrafine Mo composite containing dispersed Al2O3 particles with stable boundary adhesion can efficiently hinder dislocation movement and crack propagation, resulting in the obvious enhancements of bending strength, hardness and compressive yield strength.

Comparison between nitriding behavior of Mo-Ti and Mo-V alloys

Internal nitriding behavior of Mo-15 at.% Ti and Mo- 5/15 at.% V alloys were compared in a temperature range from 700 °C to 1100 °C using Forming gas (95% N2 and 5% H2) for nitriding times of 10 h and 15 h. The variations of specimen weight, microstructure and hardness of nitrided layer as well as the developed nitriding products were investigated as a function of treatment temperature and time. VN and TiN nitrides with a minor amount of TiO2 oxide are formed on the surface of Mo-V and Mo-Ti alloys, respectively. The maximum nitrided depths of around 14 μm are achieved for both Mo-15 Ti/V alloys after nitriding at 1100 °C for 10 h. Larger hardness values are measured on nitrided layer of Mo-Ti in comparison to that of Mo-V at the same treatment temperature. According to X-ray diffraction assessment, at moderate temperature of 900 °C, the diffraction of Mo matrix and VN nitrides is recognized as an incoherent diffraction, whereas coherent diffraction by matrix and nitrides is realized for Mo and TiN. In general, higher affinity of nitride formation for V is observed at lower temperature of 700 °C as compared to Ti in a Mo matrix, which is attributed to the stronger interaction of V and N in Mo matrix given by calculating corresponding interaction parameters. The difference in stress relieving and coarsening behavior were also observed in matrices containing VN and TiN, which is argued with regards to the dissimilar impacts of VN and TiN on precipitation hardening of Mo matrix at investigated temperatures. These results imply that the previously reported brittleness of Mo-based alloys containing Ti can be improved at moderate temperatures by replacing Ti with other nitride forming elements such as V, regardless of N concertation in Mo matrix.

High-temperature Oxidation Properties of TiC-reinforced Mo Matrix Composites with Cr Element Added

This work studied Mo-TiC-xCr (x = 0.0, 0.5, 1.0 wt.%) matrix composites with different component gradients prepared by Spark Plasma Sintering (SPS). The high-temperature oxidation test was conducted at 1200 ℃ in the atmosphere to study the influence of Cr on the high-temperature oxidation behavior of TiC-reinforced Mo matrix composites. The phase composition and morphology of the oxide film were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS), and the goal was to determine the effect of the Cr content on the high-temperature oxidation properties of the Mo-TiC-xCr (x = 0.0, 0.5, 1.0 wt.%) matrix composites. The results showed that with increasing oxidation time, the oxide film on the surface of Mo alloy will crack and fall off easily, and the porosity gradually increases. Oxygen underwent vigorous oxidation through the pores and the inside of the matrix, and a protective MoO2 internal oxide film disappeared. With increasing Cr content, the high-temperature oxidation performance of the Mo alloy improved, the thickness of the oxide film decreased, warping of the surface oxide film was inhibited, the porosity decreased, and volatilization of MoO3 was inhibited. After oxidation, the surface oxide film was mainly composed of TiO2, MoO3, Cr2O3 and Cr2(MoO4)3 phases. The TiC particles dispersed in the matrix were oxidized to TiO2 to inhibit the oxidation of the alloy. The Cr formed a protective oxidation film of Cr2O3, which effectively reduced the porosity and delayed the volatilization of the MoO3, thus improving its oxidation performance.

In situ phase interface engineering of MoLa alloys for enhanced strength

Incoherent interphases and oxygen segregation at the grain boundaries (GBs) significantly deteriorate the strength of Mo-based alloys. In this study, a new additive, LaB6, was proposed to enhance the mechanical properties. It was found that LaB6 reacted with the matrix to generate coherent La2O3, volatile B2O3 and tiny MoB in situ during sintering. The addition of LaB6 does not increase strength by itself, but can limit grain growth and construct a coherent interface between the as-obtained La2O3 and Mo matrix. More importantly, the oxygen impurity is removed by B in the form of B2O3, which purifies the GBs. As a result, the as-sintered Mo-La-B billets present an extremely high ultimate tensile strength of 965 MPa, which is among the best recorded values for all sintered Mo-based alloys. The enhanced strength can be attributed to the refined grain size, coherent phase interface, and purified GBs.

Investigation of microstructures, defects, and mechanical properties of titanium-zirconium-molybdenum alloy manufactured by wire arc additive manufacturing

Titanium‑zirconium‑molybdenum (TZM), one of the refractory alloys, has extraordinary physicochemical properties, making it ideal for usage in extreme environmental applications (e.g., high-temperature and nuclear). Due to the scalability and near-net shape fabrication, metal additive manufacturing processes have several advantages, leading it to be the possible solution for the fabrication of refractory alloy structures. Wire arc additive manufacturing (WAAM) has several advantages, including high deposition rate, energy efficiency, and cost-effective manufacturing of large components. In this study, we comprehensively investigated the relationships among process, microstructures, mechanical properties, and defects of TZM thin-walls manufactured by WAAM using four heat input conditions: 180A, 200A, 220A, and 240A. The microstructures were investigated using multi-scale material characterization techniques. Columnar grains were generated along the build direction, and carbide precipitates were found uniformly distributed in the Mo matrix. Multi-scale pores and cracks were present in the microstructures. The average microhardness values for the deposits ranged from 188.5 to 193.5 hardness scales of Vickers. The highest yield strength, 195 MPa, was found in the 200A heat input condition. The primary fracture mode was identified as a brittle transgranular. The area fraction of porosity was calculated >1% in each condition, with the largest being 2.04% in the 240A deposit.

Formation mechanism of coronal composite secondary phase in titanium-zirconium-molybdenum alloy

The coronal composite secondary phase has a high mismatch tolerance with the molybdenum matrix. TiO 2 particles located within the coronal structure that provide a semi-coherent interface with a mismatch degree of 8.70%, and ZrO 2 particles located outside the coronal structure that provide an incoherent interface with a mismatch degree as high as 41.61%. The ZrO 2 particles of the coronal composite secondary phase are partially attached to the TiO 2 in a coronal structure, which endows the ZrO 2 with the molybdenum matrix's higher interfacial bonding force. Titanium sulfate and zirconium nitrate are realized the mixing of Ti/Zr, TiO 2 /ZrO 2 molecules at atomic levels. Compared with Ti, Zr is more easily combined with oxygen, which leads to Zr in Ti/Zr solid solution being attracted by oxygen at high temperature to form ZrO 2 . The small addition of zirconium element lacks nucleation particles to form of ZrO 2 , so ZrO 2 can only adhere to more TiO 2 particles and nucleate, forming the second phase of the coronal composite structure. This study can guide the design of high-performance secondary phase strengthening alloys. • The coronal composite secondary phase and the Mo matrix have a high tolerance of mismatch degree. • ZrO 2 particles are attached to TiO 2 , which endows ZrO 2 with a higher interfacial bonding force with Mo. • The secondary phase particles have a fine particle size, uniform distribution, and strong adhesion. • Mixing at the molecular or atomic level, Zr is oxyphilic, enabling the formation of the coronal composite secondary phase.