Enhancement of mechanical properties of low stacking fault energy brass processed by cryorolling followed by short-annealing

Effect of Annealing Temperature on Microstructure and Mechanical Properties of Ultrafine Grained Brass Produced by Equal Channel Angular Pressing

“…Furthermore, ductility increased significantly at 300°C. These results are in accordance with those of several previous studies (Kumar et al, 2015;Humpreys & Hatherly, 2004;Sakai et al, 2014;Ozgowicz et al, 2010;Zhao et al, 2014), indicating that annealing after great deformation decreases strain hardening due to recrystallization and grain growth occurred at lower annealing temperature, so that great deformation reduced recrystallization temperature of metal. Figure 3 Tensile properties of Cu-30%Zn alloy deformed by four ECAP passes and annealed at elevated temperatures After tensile testing, the fractured sample surfaces were examined using SEM, and the fractographs are shown in Figure 4.…”

“…At higher annealing temperatures, the hardness decreased less rapidly, reaching 122 HV at the annealing temperature of 500°C. These results are consistent with those of Kumar et al (2015), who cryorolled Cu-18Zn with a 90% area reduction, which is a large strain. After CR, the alloy's hardness was 221 HV.…”

“…They also showed that the recrystallization temperature (T R ) of the UFG brass was below 0.5 of the melting temperature (T M ), which was in accordance with the results of Humpreys and Hatherly (2004), Kumar et al (2015), and Ozgowicz et al (2010). Kumar et al (2015) reported that deformation using CR with 90% area reduction and annealing at 200°C to 300°C produced Cu-18Zn brass with a microstructure in which subgrain size had increased from 48 to 106 nm. This indicates that the microstructure changed significantly after annealing at temperatures from 200°C to 300°C.…”

“…SPD can deform metal microstructure to UFG or nano-sized grains (nanocystallins). Several SPD methods have been developed, including high-pressure torsion (HPT) (Zhilyaev et al, 2014;Valiev & Langdon, 2006), accumulative roll bonding (ARB) (Pasebani & Toroghinejad, 2010;Azushima et al, 2008;Valiev et al, 2000), multidirectional forging (MDF) (Gubizca et al, 2011;Azushima et al, 2008), rolling at cryo temperatures (cryorolling, (CR)) (San et al, 2012;Kumar et al, 2015), and equal channel angular pressing (ECAP) (Suryadi et al, 2013;Bahadori et al, 2013;Azushima et al, 2008). ECAP, first introduced by Segal in the 1970s and 1980s (Valiev & Langdon, 2006), has considerable SPD potential, enabling it to produce UFG metals with relatively large dimensions.…”

“…It is important to note that such processing changes the metal's characteristics, including its mechanical properties and microstructure, and deforms the UFG metal Combinations of SPD and advanced processing have been performed. One study produced UFG metal of Cu-18Zn using CR with 90% area reduction, followed by short annealing (Kumar et al, 2015). This combination produced nanostructures of 48 nm and significant changes in mechanical properties after annealing at various temperatures.…”