In this study, the microstructure, tensile, and fatigue behavior of the COPPER matrix composites reinforced by STEEL particles are investigated. The composite grades containing 2. 5, 5. 2, and 7. 4 wt% STEEL particles up to 90 μ, m in size are manufactured by the casting method. The microstructure of the composite samples is studied by scanning electron microscopy. The tensile and fatigue test samples are prepared and tested based on the ASTM standard. Adding 2. 5 wt% STEEL particles to the COPPER matrix increases the yield strength, tensile strength, and elongation of the pure COPPER by about 48, 21, and 4. 8%, respectively. The fatigue test results show that reinforcing the pure COPPER with 2. 5 wt% STEEL particles improves the fatigue life of the pure COPPER by 67, 31, and 86 percent in 60, 80, and 100 MPa amplitude stresses, respectively. On the other hand, further increasing the reinforcement particle content to 5. 2 and 7. 4 wt% causes unusual fatigue behavior and adversely affects the mechanical strength of the composite. Therefore, the fatigue life of the composite samples reinforced by more than 5. 2 wt% STEEL particles is not a function of the stress level and does not increase with the decrease of the stress.

Minimum quantity Lubrication (MQL) is a technique used to reduce the utilization of cutting liquids in accomplishing a perfect and well-disposed condition. In this examination, the machinability of M2 STEEL which is hard-to-machine material utilized in key applications was researched under three separate cutting strategies such as dry environment, oil environment, and COPPER nanofluids with minimum quantity lubrication as environment. The turning tests were conducted utilizing carbide inserts on five separate cutting speed with constant feed and depth of cut. The maximum roughness value obtained with dry condition is 3.75 µm, for oil is 1.7 µm and nanofluid is 0.81 µm. The extreme flank wear values attained is 0.16 mm, 0.055 mm and 0.04 mm for dry, oil and nanofluid conditions. The reduced value of surface roughness (0.45 µm) and flank wear (0.04 mm) were obtained when the machining was performed under COPPER nanofluid as a coolant.

In this study, COPPER matrix composites reinforced by 2. 5, 5. 5, and 8 wt% STEEL nanoparticles less than 130 nm in diameter were prepared by the casting method. The STEEL nanoparticles were made of STEEL machining chips. Disc mill and ball mill instruments were used to produce nanoparticles from machining chips. COPPER was melted using an induction furnace, and the STEEL nanoparticles were injected into the COPPER melt by gas gun. The nanoparticle content effect on microstructure, mechanical properties, fracture toughness, and electrical conductivity of the composites are investigated in this paper. Increasing the reinforcement content to 2. 5 wt% in the produced composite increases the yield strength, tensile strength, and ductility by 20%, 49%, and 13%, respectively, and then the strengthening effects deteriorate. By increasing the nanoparticle content, elongation and ductility almost continuously increase. Maximum elongation and Charpy impact energy of 90 J and 37% are achieved in this research for the composite grade reinforced by 8 wt% of STEEL nanoparticles that these values are almost 8. 2 and 1. 2 times greater than impact energy and elongation of the pure COPPER sample. Furthermore, the addition of STEEL nanoparticles shows a little adverse effect on the electrical conductivity but dramatically improves the composite toughness.

The openings of COPPER converter in Sarcheshmeh COPPER Complex in Iran is made of a heat resisting austenitic STEEL (Fe-25Cr-12Ni) and many failures have been reported. Understanding the failure mechanism of the alloy helps to develop better alloys for similar complex environments. Samples of as-cast alloy and those taken from failed ones were examined. Optical Microscopy (OM), X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) have applied to examine the alloy and oxide scales. Investigations show that microscopic structure and operational conditions are parameters which affect the fracture of the alloy. The existence of SO2 in the environment increases the reaction rate and formation of sulphides comes near the surface and around the grain boundaries. The sulphides decrease the oxidation resistance of the alloy.

Background: We aimed to investigate the effect of COPPER stainless STEEL on apoptosis of vascular smooth muscle cells in coronary artery. Methods: The study was carried out in 2019 at Hubei University of Medicine, Xiangyang, China. The rat cor-onary artery smooth muscle cell was used for cell resuscitation and culture. MTT method was used to visualize cell growth curve and to detect the cell survival and growth. The incubated cells were randomly divided into COPPER-containing stainless-STEEL group, ordinary stainless-STEEL group, and control group. The cells were made into single cell suspension, which were intervened by experimental group and incubated in incubator with CO2 for 48 hours. TUNEL method was used to detect the apoptosis. The number of apoptotic cells in five high power fields (×200) was counted. The expression of Fas protein in three groups of cells was detected by West-ern blot. Results: The growth curves of rat coronary artery smooth muscle cells showed that the OD value of the cells reached the plateau 7 days after inoculation, indicating that the cells grew well. TUNEL staining showed the apoptosis in all three groups. The apoptotic index in COPPER-containing group was significantly higher than that in common stainless-STEEL group (P <0. 01). The results of the Fas protein expression level through Western blot showed that the level in the COPPER-containing group was significantly higher than that in the common stainless-STEEL group (P<0. 01). Conclusion: COPPER-containing stainless STEEL can promote apoptosis of coronary artery smooth muscle cells. The material could prevent stent restenosis.

Electrical kindling is a popular model for studying epilepsy, which is similar to complex focal seizures in humans. In this method, by implanting metal electrodes in the brain and subthreshold stimulation, the animal acquires chronic convulsions. This study aimed to compare the development of rapid electrical kindling using STEEL and COPPER electrodes in adult male Wistar rats. Tri-polar STEEL or COPPER electrodes and two unipolar electrodes were stereotaxically embedded in the basolateral nucleus of the amygdala or the skull surface, respectively. One week later, the threshold current intensity was determined. Twenty-four hours afterward, animals received six stimulations per day with the threshold intensity until they showed three consecutive stage five seizures. The animals were then perfused, and their brains were fixed, stained, and examined histologically. The results showed that animals with the STEEL electrode had a significantly lower threshold than those with a COPPER electrode. In addition, the number of stimulations for seizure generalization was significantly lower in the STEEL group. The amount of tissue damage in the experimental groups was not significantly different; however, the number of dead cells in the STEEL groups was significantly lower than that in the COPPER groups. In conclusion, although animals were kindled with COPPER electrodes, they may not be suitable for use in laboratory evaluations due to the neurotoxic effects of COPPER, which lead to tissue damage and delays in seizure parameters. Therefore, the results of such studies can be misleading.