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CoCrCuFeMnNix (x = 0 mol, 0.5 mol, 1.0 mol, 1.5 mol, and 2.0 mol, named Ni0, Ni0.5, Ni1.0, Ni1.5, and Ni2.0, respectively) high-entropy alloys (HEAs) were prepared using vacuum hot pressing sintering. The atmospheric oxidation behavior of the alloys was studied using a constant-temperature oxidation discontinuous weighing method. The kinetic curve of the alloys after oxidation at 800°C for 50 h follows a parabolic law. A high Ni content corresponds to a small oxidation weight gain of the alloy. After 50 h of oxidation, the oxidation weight gain and oxidation rate constant Kp value of Ni2.0 alloy are the smallest at 3.03 mg/cm2 and 6.59 × 10−12 g2 cm−4 s−1, respectively. The outer oxide layer of the alloys is composed of loose and porous Mn-containing oxides (Mn4O3 or Mn3O2), and the dense layer is composed of continuous and dense Cr2O3. The increase in Ni content promotes the formation of NiCr2O4 oxides with a spinel structure, inhibits the formation of porous MnO, improves the thermal stability of FCC phase, and weakens the volatilization of Cr2O3, thereby improving the oxidation resistance of HEAs. The oxidation mechanism of the alloys is mainly selective oxidation, which involves the outward diffusion of metal cations and the inward permeation of oxygen ions. [ABSTRACT FROM AUTHOR]

This study investigated four cooling methods for CuCrFeMnNi high-entropy alloy, namely, furnace cooling, air cooling, oil cooling, and water cooling (designated as FC, AC, OC, and WC, respectively), following a 12 h treatment at 800 °C. Results indicate that all four cooled alloys consisted of two FCC solid-solution phases (FCC1 and FCC2) and ρ phases. However, the FC alloy primarily contained FCC2 as the main phase and FCC1 as the secondary phase. The other three cooling methods yielded alloys with FCC2 as the primary phase and FCC1 as the secondary phase. With an increase in cooling rate, the content of the FCC1 phase gradually increased, that of the ρ phase initially decreased and then increased, and that of the FCC2 phase gradually decreased. The microstructure of the CuCrFeMnNi high-entropy alloy under the four cooling methods consisted of gray-black dendrites rich in Cr-Fe and white dendrites rich in Cu. Black ρ-phase particles predominated the dendrite region. As the cooling rate increased, the white interdendritic regions shrank, and the gray-black interdendritic regions expanded. The FC alloy exhibited the lowest microhardness at approximately 202.6 HV. As the cooling rate increased, the microhardness of the alloy progressively increased. The microhardness of the WC alloy was the highest, at approximately 355 HV. The strengthening mechanisms for all the alloys were primarily solid-solution strengthening and second-phase precipitation strengthening. [ABSTRACT FROM AUTHOR]

CoCrCuFeMnNix (x = 0, 0.5, 1.0, 1.5, 2.0 mol, named as Ni0, Ni0.5, Ni1.0, Ni1.5, and Ni2.0, respectively) high-entropy alloy powders (HEAPs) were prepared via mechanical alloying (MA), and XRD, SEM, EDS, and vacuum annealing were used to study the alloying behavior, phase transition, and thermal stability. The results indicated that the Ni0, Ni0.5, and Ni1.0 HEAPs were alloyed at the initial stage (5–15 h), the metastable BCC + FCC two-phase solid solution structure was formed, and the BCC phase disappeared gradually with the prolonging of ball milling time. Finally, a single FCC structure was formed. Both Ni1.5 and Ni2.0 alloys with high nickel content formed a single FCC structure during the whole mechanical alloying process. The five kinds of HEAPs showed equiaxed particles in dry milling, and the particle size increased with an increase in milling time. After wet milling, they changed into lamellar morphology with thickness less than 1 μm and maximum size less than 20 μm. The composition of each component was close to its nominal composition, and the alloying sequence during ball milling was Cu→Mn→Co→Ni→Fe→Cr. After vacuum annealing at 700~900 °C, the FCC phase in the HEAPs with low Ni content transformed into FCC2 secondary phase, FCC1 primary phase, and a minor σ phase. The thermal stability of HEAPs can be improved by increasing Ni content. [ABSTRACT FROM AUTHOR]

Objective: To analyze the conservative management and outcomes of pharyngocutaneous fistula after total laryngectomy., Method: Twenty-one patients with postoperative fistulas were identified and treated by conservative therapy., Result: Different treatment were given basing on the three stages of pharyngocutaneous fistula: drainage and cleaning stage, pressure bandaging stage and healing stage. Fourteen patients (66.7%) with the conservative therapy resumed oral feeding after closure of fistula, the other 7 patients had to be cured by further operation., Conclusion: Management basing on the stages of pharyngocutaneous fistula can achieve satisfied outcome. It can provide important information for pharyngocutaneous fistula's treatment.

Objective: To investigate the clinical application of quantitative evaluation of the focus range of juvenile onset recurrent respiratory papillomatosis (JO-RRP)., Method: Disease severity was scored as the sum of ratings of 1 (minimal), 2 (moderate), or 3 (severe) for involvement of 22 areas of the respiratory tract and digestive tract. Sixty-eight cases with JO-RRP patients underwent 238 procedures were removed papillomas. A Storz laryngoscope was used to exposed and suspend the larynx, and an endoscope video system was used to display the pathological changes., Result: The score of these cases range from 2 to 20, most of them range from 7 to 14. Papillomas were found in the larynx in each case, vocal cords and false vocal cords were the most common places involved. Nose, pharynx, hard palate, lung or esophagus involved was seldom found. The score declined as the patients underwent more procedures. It is in accord with the clinical characteristic of JO-RRP., Conclusion: We concluded that our means of JO-RRP focus range quantitative evaluation could evaluate the severity and clinical curative effect objectively. It was a scientific and convenient way, and worth to be generalized.