Dislocation structure of Ge crystals grown by low thermal gradient Czochralski technique

Surf. Topogr.: Metrol. Prop.

Zhu

et al. 2021

In the study, the surface modification of 4Cr5MoSiV steel through gas tungsten arc welding (GTAW) was carried out. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to investigate the evolution of phases and microstructures before and after the GTAW surface modification treatment. The microhardness, tribological behavior, and high-temperature oxidation property were systematically investigated using the tests regarding microhardness, high-temperature wear, and high-temperature oxidation. GTAW remelting process generated (FCC + BCC) dual phase, which created mutual restriction between the two phases in plastic deformation. Continuous distribution of hard Cr3C2 carbides at grain boundaries could disperse local stresses. The microhardness of the GTAW remelting layer was significantly improved, and the GTAW remelting increased the V element of the free state and formed V2O5 oxide with unique lattice structure in the oxide layer. The high-temperature oxidation performance of the GTAW remelting layer was slightly deteriorated. The high-temperature oxidation duration for the high-temperature wear test was short, and the high hardness of remelting layer and the connective carbides together played the major roles, so GTAW remelting layer had excellent resistance to high-temperature wear resistance.

Section: High-temperature Wear Propertymentioning

confidence: 99%

Effect of surface modification through GTAW on high-temperature performance of 4Cr5MoSiV steel

Cai

Surf. Topogr.: Metrol. Prop.

Zhu

et al. 2021

“…Compared with the BCC crystal lattice, the FCC crystal lattice has the same slip systems but more glide directions [20][21][22]. The plastic deformation in the BCC structure is governed by screw dislocations, while that in FCC structure is governed by edge dislocations [23,24]. Therefore, plastic deformation occurs more easily in the FCC structure than in the BCC structure.…”

Section: Micro-hardness and Tribological Behaviourmentioning

confidence: 99%

Influence of high-temperature condition on the microstructure and properties of FeCoCrNiAl_0.3 and FeCoCrNiAl_0.7 high-entropy alloy coatings

Cai

Zhu

et al. 2020

Surface Engineering

In the present study, FeCoCrNiAl x (x = 0.3, 0.7) coatings were fabricated by laser cladding technology. XRD analysis and scanning electron microscopy (SEM) were used to investigate the evolution of phases and microstructures before and after the high-temperature oxidation test. The micro-hardness, tribological behaviour, and corrosion resistance of the coatings, before and after the high-temperature treatment, were systematically investigated using micro-hardness test, abrasive wear test, and electrochemical corrosion test. The microstructure and properties of FeCoCrNiAl 0.3 cladding layer changed little before and after the high-temperature oxidation test. The high-temperature condition promoted the generation of BCC solid solutions at the grain boundaries when the Al element content was 14.89% (i.e. 0.7 mol). This enhanced the micro-hardness and tribological behaviour, but deteriorated the corrosion resistance.

“…An FCC structure has more slip direction and smaller Burgers vector than a BCC structure. It also contains more slip-conducive edge dislocation for motion, which is more likely to cause plastic deformation [21][22][23][24][25]. Therefore, the BCC phase has a greater ability to resist plastic deformation and plays a solid solution strengthening role in the FeCoCrNiMnAl 0.75 coating.…”

Section: Phase and Microstructure Of The Fecocrnimnal X Coatingsmentioning

confidence: 99%

Oxidation and Wear Mechanisms of FeCoCrNiMnAlx Cladding Layers at High-Temperature Condition

Shen

et al. 2020

Coatings

FeCoCrNiMnAlx high-entropy alloy (HEA) cladding layers were successfully fabricated on H13 steel by laser cladding. The microstructure and properties of the FeCoCrNiMnAlx HEA cladding layers were systematically studied. The influence of Al content on high-temperature wear resistance of HEAs was investigated by depth-of-field microscopy, XRD, SEM and EDS. Addition of Al element affected the mechanism of oxidation and strengthening of the cladding layers, and effectively promoted its anti-oxidant and abrasion resistance. Compared with the FeCoCrNiMn cladding layer, the FeCoCrNiMnAl0.75 cladding layer enhanced the anti-plastic deformation capacity by 7.1% and reduced oxidation weight gain and total wear weight loss at high temperature by 36.79% and 79.0%, respectively. The wear mechanisms of the cladding layer at high temperature were mainly oxidation wear and abrasive wear, while adhesive wear took a backseat.