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The WC and high chromium cast iron (HCCI) welded layers were prepared on Q235 low carbon steel by hardfacing technique in order to improve high-temperature performance. The microstructure and mechanical properties of the welded layer were investigated. It was found that Fe3W3C is the major strengthening phase of the WC welded layer. Furthermore, a high-temperature three-body abrasive wear experiment was designed and conducted on the welded layers. The results show that the wear resistance of the WC welded layer was much better than that of the HCCI welded layer at both room and high temperatures. During the high-temperature abrasive wear process, the Fe3W3C phase can effectively strengthen the matrix and hence, contribute to improved wear resistance.

In the field of metal matrix composites, it is a great challenge to improve the strength and elongation of magnesium matrix composites simultaneously. In this work, xTC4/AZ31 (x = 0.5, 1, 1.5 wt.%) composites were fabricated by spark plasma sintering (SPS) followed by hot extrusion. Scanning electron microscopy (SEM) showed that nano-TC4 (Ti-6Al-4V) was well dispersed in the AZ31 matrix. We studied the microstructure evolution and tensile properties of the composites, and analyzed the strengthening mechanism of nano-TC4 on magnesium matrix composites. The results showed that magnesium matrix composites with 1 wt.%TC4 had good comprehensive properties; compared with the AZ31 matrix, the yield strength (YS) was increased by 20.4%, from 162 MPa to 195 MPa; the ultimate tensile strength (UTS) was increased by 11.7%, from 274 MPa to 306 MPa, and the failure strain (FS) was increased by 21.1%, from 7.6% to 9.2%. The improvement in strength was mainly due to grain refinement and good interfacial bonding between nano-TC4 and the Mg matrix. The increase in elongation was the result of grain refinement and a weakened texture.

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Improving strength without sacrificing toughness is a permanent request for the development of advanced engineering materials. Herein, a novel energy‐saving strategy is developed to obtain strong but tough low‐alloyed steels. A medium‐carbon steel (42CrMo) is used for demonstration. Warm deformation (tempforming) is applied to the hot‐rolled and air‐cooled 42CrMo steel. After tempforming, the microstructure consists of nano‐sized carbides and highly textured ultrafine grains. The tensile strength of the tempformed steels can reach 1.2 GPa, while the impact toughness is higher than 100 J even at temperatures as low as −80 °C, which are one order of magnitude higher than the counterpart steel after tempering. The present work sheds light on the design and fabrication of high‐performance engineering steels with an excellent combination of strength and toughness.

In this paper, a new nanoscale metal Ti particle-reinforced Mg-3Al-1Zn matrix composite was successfully designed and prepared, which is mainly characterized by the fact that in addition to the “light” advantages of magnesium matrix composite, it also realizes bidirectional improvement of strength and ductility of the composite, and can be used as an alternative material for military light vehicle armor and individual armor. The SEM test shows that the nano-Ti particles are uniformly distributed at the grain boundary under the extruded state, which nails the grain boundary, inhibits the grain growth, and significantly refines the grain. XRD tests show that the addition of nano-Ti particles increases the crystallinity of the composite, which is consistent with the SEM test results. In addition, the EBSD test shows that the weakening of the texture of Ti/Mg-3Al-1Zn matrix composites and the increase in the starting probability of slip system are the main reasons for the improvement in ductility. Mechanical tests show that the yield strength, tensile strength, and elongation of the 0.5 wt% Ti/Mg-3Al-1Zn matrix composites exceed the peak values of ASTM B107/B107M-13 by 38.6%, 26.7%, and 20%, respectively.

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