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Developing light yet strong aluminum (Al)-based alloys has been attracting unremitting efforts due to the soaring demand for energy-efficient structural materials. However, this endeavor is impeded by the limited solubility of other lighter components in Al. Here, we propose to surmount this challenge by converting multiple brittle phases into a ductile solid solution in Al-based complex concentrated alloys (CCA) by applying high pressure and temperature. We successfully develop a face-centered cubic single-phase Al-based CCA, Al55Mg35Li5Zn5, with a low density of 2.40 g/cm3 and a high specific yield strength of 344×103 N·m/kg (typically ~ 200×103 N·m/kg in conventional Al-based alloys). Our analysis reveals that formation of the single-phase CCA can be attributed to the decreased difference in atomic size and electronegativity between the solute elements and Al under high pressure, as well as the synergistic high entropy effect caused by high temperature and high pressure. The increase in strength originates mainly from high solid solution and nanoscale chemical fluctuations. Our findings could offer a viable route to explore lightweight single-phase CCAs in a vast composition-temperature-pressure space with enhanced mechanical properties. By overcoming the limited solubility of other lighter components in aluminum using high pressure and high temperature, a low-density, high specific strength, and single-phase aluminum-based complex concentrated alloy is developed. [ABSTRACT FROM AUTHOR]

AlxCrFeNi (x = 1.25, 1.5, 1.75, 2.0) EHEAs were introduced by different coupling structures. Grain refinement triggered the continuous improvement of ductility with the increase of Al content. Double strengthening phases and grain refinement effect could be evolution of different coupling structures in strain-hardening-rate response of AlxCrFeNi. Specifically, alloy's structure evolved from the coupling of mesh structure and labyrinth structure to completely labyrinth eutectic structure with the increase of Al content from 1.25 to 1.75, and the compressive mechanical properties appeared acute increased. Meanwhile, the ductility, yield strength and ultimate strength of Al1.75 reached 11.7%, 1325.4 MPa and 1621.0 MPa, respectively, which was significantly excellent compared to Al1.25 and Al1.5. It ascribed to the more stable combination of the two-phase cross labyrinth structure and stronger resistance to external impact. [ABSTRACT FROM AUTHOR]

The Fe49.7Cr18Mn1.9Mo7.4W1.6B15.2C3.8Si2 amorphous coating was deposited on T91 steel substrate by using the high-velocity oxygen fuel (HVOF) spray technique to enhance the corrosion resistance of T91 stainless steel in liquid lead-bismuth eutectic (LBE). The corrosion behavior of the T91 steel and coating exposed to oxygen-saturated LBE at 400°C for 500 h was investigated. Results showed that the T91 substrate was severely corroded and covered by a homogeneously distributed dual-layer oxide on the interface contacted to LBE, consisting of an outer magnetite layer and an inner Fe−Cr spinel layer. Meanwhile, the amorphous coating with a high glass transition temperature (Tg = 550°C) and crystallization temperature (Tx = 600°C) exhibited dramatically enhanced thermal stability and corrosion resistance. No visible LBE penetration was observed, although small amounts of Fe3O4, Cr2O3, and PbO were found on the coating surface. In addition, the amorphicity and interface bonding of the coating layer remained unchanged after the LBE corrosion. The Fe-based amorphous coating can act as a stable barrier layer in liquid LBE and have great application potential for long-term service in LBE-cooled fast reactors. [ABSTRACT FROM AUTHOR]

Lead-bismuth eutectics (LBE) have considerable potential as a candidate material for accelerator-driven sub-critical systems (ADS). However, LBE corrosion and irradiation damage are two urgent challenges remaining to be solved for impellers of primary pumps. In this study, we have explored the possibility of using Fe-based amorphous coatings to overcome LBE corrosion and concurrently to sustain irradiation damage. Specifically, the Fe54Cr18Mo2Zr8B18 amorphous coating was prepared by high-velocity oxygen-fuel (HVOF) spraying on 316L steel and exposed to saturated oxygen static LBE for 500 h at 400°C. The coating with high thermal stability (Tg=615°C and Tx=660°C) effectively prevented the substrate steel from being corroded by LBE owing to its unique long-range disordered atomic packing. The coating also exhibited strong irradiation resistance when being subjected to 45 dpa (displacement per atom) Au ion irradiation at room temperature, with no sign of crystallization even at the maximum implantation depth of 300 nm. Consequently, the hardness of the coatings before and after irradiation increased slightly. The current findings shed new insights into understanding corrosion mechanism and irradiation behavior of amorphous solids in LBE and expand the application range of amorphous materials. [ABSTRACT FROM AUTHOR]

The secondary explosive welding process promotes the diffusion of the carbon element and accumulation of chromium carbide, which leads to a decrease of tensile properties and toughness of the material. In this work, the average shear strength value increased from 400 to 421 MPa. The crack of the fatigue specimens started from the inclusions rich in alumina near the surface, and the harmful hard-phase inclusions were exposed because of stress concentration. The maximum load limit of 10CrNi3MoV steel undergoing secondary explosive welding was between 590 and 605 MPa. [ABSTRACT FROM AUTHOR]

In the present study, composite bimetallic plates of 10CrNi3MoV steel—304L stainless steel were butt welded by shielded metal arc welding (SMAW). A transition layer was designed to compensate for the dilution of Cr and Ni in stainless steel layer during the welding of dissimilar metals. From the results, it was seen that the lowest hardness of fusion weld was located in transition layer, followed by 304L stainless steel side, and the highest hardness occurred at 10CrNi3MoV steel area. The minimum hardness was related to high Cr and Ni in transition layer welded by E309L welding rod, and a uniform dendritic austenite structure was formed in the fusion weld. The formation of high-hardness carbides and vanadium-containing phases enhanced the hardness of the fusion weld. Butt welded joints had excellent tensile strength and toughness. The maximum tensile strength of the joint was about 694 MPa, and the tensile specimens fractured in ductile at matrix of the bimetallic plates. The impact energy of the weld joint was about 98 J at − 20 °C. When the number of loading cycles was set to 2 × 106 times, the maximum load limit of the bimetallic plate welded joint in 10CrNi3MoV steel was between 600 MPa and 625 MPa. [ABSTRACT FROM AUTHOR]

High strength low alloy (HSLA) steel 10CrNi3MoV and stainless steel 304L (SS304L) were used to manufacture bimetallic plates by explosive welding. The quality and overall performance of the bimetallic plates were evaluated in terms of microstructure and mechanical properties. Its microstructure, elemental distribution, and phase analysis of the bonding interface were investigated by means of OM, SEM, EDS, and XRD. The mechanical properties of the bimetallic plates were studied by experimental measurements, including tensile tests, shear tests, Charpy impact tests, hardness tests, and then evaluated based on the standards. Experimental evaluation showed out that HSLA 10CrNi3MoV steel and SS304L could be cladded with a good quality of bonding properties by explosive welding. The base material 10CrNi3MoV steel still maintained its inherent excellent mechanical performance, even after undergoing explosive welding process. The functional flyer layer SS304L maintained its corrosion resistance even after undergoing a process of post-weld heat treatment at high temperature 645 °C for 240 min. Shear strength of the bimetallic plates was about 432 MPa more than twice the value required by the standard. The maximum hardness value was obtained near the joint on the side of SS304L, and the minimum one appeared in the middle of the explosive welding interface. [ABSTRACT FROM AUTHOR]