Papers by Keyword: Brinell Hardness

Abstract: The objective of this work is to carry out a comparison of different materials in the form of a bidirectional carbon fabric and hybrid Kevlar and glass as reinforcements in an epoxy matrix with a loading rate of 30wt%. Two experimental tests have been carried out in order to determine the mechanical properties, such as tensile and Brinell hardness tests. In the case of tensile and Brinell hardness tests, the characterization was performed on two types of composite plates reinforced with Woven Carbon Fiber and Hybrid Woven Kevlar and E-Glass with Epoxy (WCF-HWKG/EPOXY) and Hybrid Woven Kevlar and E-Glass with Epoxy (HWKG/EPOXY). Consequently, it has been observed that the tensile and hardness properties of the hybrid composite material (HWKG/EPOXY) are respectively 36% and 46.43% lower compared to (WCF-HWKG/EPOXY). Based on these findings, the studied materials demonstrate potential applications across various fields, including aeronautics, aerospace, and high-performance automotive sectors.

Abstract: In order to improve the plasticity of the Al–Mg alloy, which fabricated by continuous casting and rolling, the alloy was heat treated at 370 °C, 400 °C, 430 °C and 460 °C for 2 hours and cooled with the furnace. The microstructure and mechanical properties of heat-treated Al–Mg alloy under different heat treatment temperatures were analyzed. The results show that the columnar grains begin to disappear at heat treatment temperature of 460 °C. The size of equiaxed grains begins to increase as the heat treatment temperature increases. The tensile strength of the alloy decreases with the increase of heat treatment temperature and the Brinell hardness increases when the heat treatment temperature is between 370-430 °C. At heat treatment of 430 °C, the elongation and the Brinell hardness of the alloy reached to 42.91% and 70.5 HB, respectively.

Abstract: The semi-solid extruded CuSn10P1 alloy bushings were homogenization annealed. The effects of annealing process on the hardness and wear properties of bushings were researched. The results show the Brinell hardness increases firstly and then decreases with the increase of annealing temperature and annealing time. With the annealing temperature increasing, the grinding loss rate and friction factor decrease firstly and then increase. At the annealing time of 120 min, the grinding loss rate decreases from 7% at the annealing temperature of 450 °C to 6% at 500 °C, and then increases from 6% at 500 °C to 12% at 600 °C. The friction factor decreases from 0.54 to 0.48 and then increases to 0.83. At the annealing temperature of 500 °C, the grinding loss rate decreases from 11% at the annealing time of 60 min to 6% at 120 min, and then increases to 15% at 150 min. The friction factor decreases from 0.67 to 0.48 and then increases to 0.72. The best wear performance and Brinell hardness can be obtained at annealing temperature of 500 °C for 120 min.

Abstract: The paper studies issues related to physicochemical and chemical techniques for the modification of wood-polymer composites with a thermoplastic polymer matrix (WPCs) to improve their physical and mechanical properties. The physicochemical modification was performed by photochemical crosslinking with the exposure of WPC specimens to UV irradiation. Chemical modification was performed by introducing benzoyl peroxide into the material composition, leading to chemical crosslinking of polyethylene macromolecules of the WPC polymer matrix. As a result of the study, quantitative characteristics of the effect of the benzoyl peroxide content in the composite, as well as the WPC specimen UV irradiation intensity and duration on the basic physical and mechanical properties of the material have been obtained. The efficiency of physicochemical techniques for modifying WPCs has been estimated by changing the specimen properties such as Brinell hardness, water absorption, and impact strength. It has been found that the Brinell hardness increases by 80 % as compared to unmodified WPC specimens. Effective modification of wood-polymer composites with polymer matrices based on high-density polyethylene may lead to a significant improvement in the quality of products made of these materials.

Abstract: This presentation focuses on the high-frequency of cyclic measurement that can be used for minimizing the effect of mechanical hysteresis. By this experiment, the investigating conditions include the periods of cyclic loading were varied as following: 1500, 1250, 1000, and 500 counts per period and the time interval between the periods of cyclic loading was fixed at 1 hour. After modifying procedures, it was found that the linearity of characteristic curve with condition of 500 counts per period demonstrated more clearly than random one. Finally, the linking between the Active Weight Loading (AWL) and the Weight Loading (WL) elucidated using the characteristic curves, while, the cyclic measuring of AWL exhibited in the ranging: 7.0 to 110.0 N which were exhibited using the Graphical User Interface (GUI), respectively.

Abstract: The relationship between tensile strength σ_В and Brinell hardness HB of different grey cast irons was investigated. It was found that at the same hardness values the tensile strength of different specimens may differ by almost two times. It was shown that the mentioned above tensile strength scatter is caused by the different volume fraction of dendritic crystals of a primary austenite f_dc. The quantitative relationships between σ_B and f_dc for in situ tensile strength assessment were established. The comparison of σ_B values calculated through Brinell hardness HB and through volume fraction of dendritic crystals f_dc shows that the latter method developed in the present paper provides more reliable results.

Abstract: The TiN-Al composite coatings on A356 alloy were successfully synthesized by mechanical alloying (MA) of Al, TiN and C powders under argon atmosphere. Meanwhile, the optimal parameters for mechanical milling processing were determined by changing the material ratio (Al: TiN: C), milling time and the ball-to-powder weight ratio, which might have a significant improvement on the wear resistance of A356 alloys. The microstructures and mechanical properties of A356 alloy samples with TiN-Al composite coatings were characterized by means of X-ray diffraction (XRD), scanning electron microscope (SEM) equipped with energy dispersive X-ray spectroscopy (EDS) and Brinell hardness test. It was found that under the optimal conditions, i.e. the material ratio of (Al: TiN: C= 17.5:1.5:1), the ball-to-powder weight ratio of 14:1 and the milling duration of 12 h, the Brinell hardness of sample-6 could be remarkably increased to 143.80 HBW. With the TiN-Al coatings fabricated by MA process, the mechanical properties of aluminum alloys could be significantly improved.

Abstract: The paper presents research on the effects of magnesium content on electrical and mechanical properties of materials after heat treatment of the casting of aluminum alloys: AlSi5Mg0.3, AlSi5Mg0.8 and AlSi5Mg1. The proposed heat treatment consisted of homogenisation at 535°C during period of the time 8 h, quenched to water and artificial aging at temperatures ranging from 120 to 240°C during period of the time to 24 h. Determination of strength properties were realized by Brinell hardness measurements. Electrical properties are in the form of electrical conductivity. The research program also included analysis of the microstructure of selected alloys.

Abstract: The present investigation involves studying the mechanical properties of the fabricated aluminium 7075 hybrid metal matrix composites reinforced with various weight % of SiC and Al₂ O₃ particulates by stir casting method. The Al 7075 hybrid metal matrix composites specimen were fabricated using L₉ orthogonal array. The mechanical properties like Brinell Harness (BHN), Rockwell Hardness (HRC) and impact loads were experimented. The mechanical properties like hardness and impact loads have improved with the increase in weight percentage of SiC and Al₂O₃ particulates in the hybrid aluminium matrix.

Abstract: The contribution deals with estimation of tensile properties and fatigue behavior based on hardness measurement. First of all the database of tensile and fatigue properties vs. hardness data was created for a group of steels, from literature survey and performed experiments. Tensile strength, yield strength, ductility and parameters of Ludwig-Hollomon equation in static and cyclic loading were extracted and fitted in relation to the hardness HB. The experimental materials were API 5 L grade steels – X60 and X70 after different deformation exposition. Measured tensile curve (SC) and cyclic deformation curve (CDC) were compared with predicted curves. Hardness was measured in-situ during cyclic loading. The maximum possible hardness values were experimentally determined. The results give a good agreement between estimated and measured data of both static tensile test and fatigue properties.