Influences of the constrained groove pressing on microstructural, mechanical, and fracture properties of brass sheets

Abstract

Constrained groove pressing (CGP) was used for the production of fine-grained brass sheets in different conditions. The process was conducted up to two cycles on brass sheets at room temperature and then half cycle at the temperature of 200 °C. Optical microscopy (OM), scanning electron microscopy (SEM), microhardness measurement, and plane stress fracture toughness was used to investigate the microstructure, mechanical properties, and fracture behavior. Microhardness measurement showed the capability of the CGP process in increasing the hardness of the refined sheets. It also showed the inhomogeneity of the hardness along the thickness of the sample after the process. The Digital Image Correlation (DIC) technique was used to investigate the elastic and plastic factors of the sheets along with the major mechanical properties of samples. The results showed a slight increase and reduction in the Young modulus and Poisson’s ratios after the process, respectively. Moreover, after two CGP cycles applying half cycle at the temperature of 200 °C did not show any significant effect on these values. The strength coefficient was as like as yield and ultimate strengths increased by increasing the number of the passes. However, processing at a higher temperature of 200 °C showed lower values for the parameters, as mentioned earlier, compared to the specimens processed at room temperature. The strain hardening index experienced a major reduction after the CGP process due to the effects of strain hardening. The anisotropy coefficient, which plays a critical factor in the severe deformation of sheets, was increased after the CGP process. However, this ratio decreased in higher passes or elevated temperatures. The highest anisotropy coefficient was obtained after the first cycle of the process. Moreover, SEM observation of the fracture surface showed shearing ductile rupture mode in the processed samples rather than ductile mode due to appearing of small and elongated dimples.

Developing methods of constrained groove pressing technique: A review

“…Some researchers also tried to process alloys to improve their mechanical properties through CGP. Khakbaz and Kazeminezhad, 69 Moradpour et al, 60 Shahmirzaloo et al, 2 and Rahul et al 66,67 found enhanced properties of Al-Mn alloy, Al-Mg alloy, brass, and stainless steel materials, respectively. The variation in mechanical properties of many materials under the influence of CGP is shown in Table 2.…”

“…1 UFG structure and a large fraction of grain boundaries lead to attractive mechanical properties such as higher strength and toughness, longer fatigue life, and better wear resistance. [2][3][4] Wherefore, the potential use of UFG materials is in the aerospace, transportation, medical devices, electronics, and defense industry. 5,6 Analytically, a Hall-Petch law is derived to relate strength and grain size (Equation ( 1)).…”

Strength enhancement and uniform strain distribution through cross route-constrained groove pressing

“…In recent years, the ultrafine-grained (UFG) materials have been the subject of extensive research characterized by a polycrystalline structure with grain sizes ranging from submicrometer (100~1000 nm) to nanometer scale (less than 100 nm) [1]. Due to their high fraction of grain boundaries and unique structure, UFG materials exhibit enhanced mechanical properties such as increased strength, toughness, superplasticity, hydrogen storage, fatigue life, radiation resistance, and wear resistance [2][3][4]. Consequently, UFG materials find promising applications in various industries including aerospace, transportation, medical devices, electronics, and defense [5,6].…”

Role of processing temperature on microstructure, mechanical properties and corrosion behavior of fine grained AZ31 magnesium alloy produced by groove pressing

“…Nickel sheets also can be conveniently processed by groove pressing and nanostructuring can be achieved to promote higher mechanical strength [11]. It is required to carry out groove pressing at worm conditions to deform copper alloys and magnesium alloys to improve the mechanical performance [12,13].…”