This study presents results of stress rupture test of MAR-M-509 cobalt alloy samples, as-cast and after surface refining with a concentrated stream of heat. Tests were conducted on samples of MAR-M-509 alloy castings, obtained using the lost-wax method. Casting structure refining was performed with the GTAW method in argon atmosphere, using the current I = 200 A and electrical arc scanning velocity vs = 100, 150, 200 and 250 mm/min. The effect of rapid resolidification of the MAR-M-509 alloy on the microstructure was examined and significant improvement in stress rupture test was observed.

In this study, different amounts of tantalum carbide (TaC) powders (5, 10 and 15 wt.%) are added to Vanadis 4 Extra steel powders. The composite powders are sintered at 1260, 1280, 1300, 1320, 1340 and 1360°C for 1 h, respectively. The experimental results showed that good mechanical properties (hardness 79.7 HRA, TRS 2246 MPa) were obtained by the addition of 10% TaC sintered at 1320°C for 1 h. Furthermore, the optimal sintered V4ES/TaC (Vanadis 4 Extra steel / TaC) composites after sub-zero treatment possess the highest hardness (80.9 HRA) and transverse rupture strength (TRS) values (2445 MPa), as well as a better polarization resistance (658.99 Ω·cm2). After sub-zero treatment, the VC carbides decompose and re-precipitate refined VC carbides within the grains (VC carbides are formed in steel powder); moreover, the TaC particles are still uniformly distributed around the grain boundaries, which results in dispersion strengthening and precipitation hardening. The results clearly reveal that sub-zero heat treatment effectively improves the microstructure and strengthens the V4ES/TaC composite.

In this work, nanosized Ni (nNi) powders of 50 nm are mixed with Cr and Ni submicron-powders (600 nm) to fabricate ­Cr-50 mass% Ni alloys by vacuum hot pressing. In order to evaluate the influence of the nanosized Ni powders, different amounts of nanosized Ni powders are added to produce the Cr-(50-x) mass% Ni-x mass% nNi alloys (x = 0, 10, 20 , and 30). The hot pressing was maintained at 1275°C, 48 MPa for 1 h. The microstructure evaluation, mechanical, and electrical properties were performed. The results reveal that mechanical and electrical properties are enhanced when increasing the nNi addition. The Cr-20 mass% ­Ni-30 mass% nNi presents the highest relative density of 96.53% and the electrical conductivity of 2.18×104 Scm–1, moreover, the hardness and transverse rupture strength values increase to 76.1 HRA and 1217 MPa, respectively. Moreover, a more homogeneous microstructure and a decrease in the mean grain size to 3.15 μm are acquired. Significantly, this fabrication procedure (adding 30 mass% nanosized nickel powders) results in the optimal microstructure, electrical and mechanical properties of submicron-structured Cr-(50-x) mass% Ni-x mass% nNi alloys.

Microwave curing of bamboo fiber increases the physical and mechanical qualities of cement concrete, according to previous studies. However, there are limited research on their endurance when used as an additive in concrete manufacturing to increase strength. The impact of bamboo fiber and Styrene Butadiene Rubber (SBR) on the mechanical and microstructure of the resulting concrete is investigated in this study. With the inclusion of bamboo fiber ranging from 0–1.5%, a mix ratio of 1:1.5:3 was used. To make the samples, 10% SBR by weight of cement was dissolved in the mixing water. The batching was done by weight, with a water cement ratio of 0.6. Compressive strength, water absorption, swelling, modulus of elasticity, and modulus of rupture were all studied as mechanical properties. Various characterization tests such as SEM, EDS, FTIR, XRD, and TGA were performed on the microstructure, crystalline nature, and mineral composition of certain samples. According to the FTIR study’s findings, peak levels were detected in the O–H stretching, C–H fiber and CH2 functional groups, carbonyl group, C–O and C–C functional groups. As the temperature climbed, TGA measurements showed a drop in weight. The XRD test revealed peak levels of 6.611, 4.255, and 3.855 for sanidine, quartz, and calcite, respectively. After 28 days, the inclusion of bamboo fibers as an additive in concrete shows some promising outcomes in compressive strength, with samples containing 1% and 1.5% bamboo fiber cured at 80°C having a higher compressive strength value.

This article asks the question to what extent Ryszard Nycz’s ambitious project of cultural practice outlined in his book Culture as Verb succeeds in opening up ‘a new form of knowledge’ and thus equipping the humanities with a fresh validity. Nycz takes up the poststructuralist concept of the humanities as a site of alternative or subversive knowledge, founded on the principles of interpretation and textual dispersion, and refocuses it on involvement (participation) and binary oppositions (borders), i.e. human vs. nonhuman, or nature vs. culture as a construct. The article, rather than addressing the issues of involvement and borders (liminality), concentrates instead on the contradictions that Nycz’ s theory gives rise to when applied to history, time and the emergence of subjectivity (identity). There is nothing objectionable about the proposition that temporal change is at the very core of culture, yet its locus must be sought not in the proclamations of individual agents, but in the conceptual ruptures that expose and reveal the boundaries of (collective) consciousness and unconsciousness, i.e. the operation of contingency.

This study mixes four different powders to produce Ti-6Cu-8Nb-xCr3C2 (x = 1, 3, and 5 mass%) alloys in three different proportions. The experimental results reveal that when 5 mass% Cr3C2 was added to the Ti-6Cu-8Nb alloys, the specimen possessed optimal mechanical properties after sintering at 1275°C for 1 h. The relative density reached 98.23%, hardness was enhanced to 67.8 HRA, and the transverse rupture strength (TRS) increased to 1821.2 MPa, respectively. The EBSD results show that the added Cr3C2 in situ decomposed into TiC and NbC during the sintering process, and the generated intermetallic compounds (Ti2Cu) were evenly dispersed in the Ti matrix. Furthermore, the reduced Cr atom acts as a β-phase stabilizing element and solid-solution in the Ti matrix. Consequently, the main strengthening mechanisms of the Ti-6Cu-8Nb-xCr3C2 alloys include dispersion strengthening, solid-solution strengthening, and precipitation hardening.