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Item Tensile Properties and Tensile Fracture Characteristics of Cast Al–Zn–Mg Alloys Processed by Equal Channel Angular Pressing(Springer India sanjiv.goswami@springer.co.in, 2017) Manjunath, G.K.; Preetham Kumar, G.V.; Bhat, K.U.In the present work, as-cast Al–5Zn–2Mg, Al–10Zn–2Mg and Al–15Zn–2Mg alloys were ECAP processed and tensile tests were carried out to determine the strength and ductility. After tensile testing, morphology of the fracture surfaces of tensile tested samples were studied. After ECAP processing, significant improvement in the yield stress and ultimate tensile strength were observed in all the three alloys. Also, yield stress and ultimate tensile strength were increased with increase in the zinc content of the material. The elongation to failure increased significantly with increase in the number of ECAP passes. SEM micrographs revealed that, the fracture surface of the cast samples of the alloys were composed of the dendritic structure, while the ECAP processed samples consisted of small size dimples. Size of the dimples were reduced with the increase in the number of ECAP passes. © 2017, The Indian Institute of Metals - IIM.Item Microstructure and Mechanical Properties of Cast Al-5Zn-2Mg Alloy Subjected to Equal-Channel Angular Pressing(Springer New York LLC barbara.b.bertram@gsk.com, 2018) Manjunath, G.K.; Preetham Kumar, G.V.P.; Udaya Bhat, K.; Huilgol, P.In the present work, cast Al-5Zn-2Mg alloy was processed through equal-channel angular pressing (ECAP) in route BC up to four number of passes. Microstructure and mechanical properties were investigated on processed and unprocessed materials. In cast condition, the material was composed of dendritic structure. After homogenization treatment, large-sized grains were observed. After ECAP processing, significant grain refinement was observed. After ECAP processing, high-density dislocations and high degree of misorientation between the grains were observed. In cast material, rod-shaped precipitates were observed, while, after ECAP processing, spherical-shaped precipitates were observed. ECAP processing leads to a noticeable improvement in the mechanical properties of the material. After four passes, 122% improvement in the microhardness and 135% improvement in the ultimate tensile strength of the material were observed. After three passes, a slight decrease in the mechanical properties was observed. This is attributed to the dissolution of the metastable ?? phase, annihilation of dislocations, dynamic recrystallization and texturing during ECAP processing. Brittle fracture mode was observed in tensile testing cast and homogenized samples. After ECAP processing, fracture mode was changed into shear fracture mode. © 2018, ASM International.Item Effect of multidirectional forging on grain structure and mechanical properties of hypereutectic Al–20%Si alloys with added refiners and modifiers; Effet du forgeage multidirectionnel sur la structure des grains et les propriétés mécaniques des alliages hypereutectiques Al-20%Si avec des agents d’affinage et modificateurs ajoutés(Taylor and Francis Ltd., 2025) Nagaraj, C.; Dutt, K.M.; Manjunath, G.K.; Sharath, P.C.; Sollapur, S.B.; B R, B.K.; Kumar, B.; Arunkumar, D.T.The present work is focused on the multidirectional forging (MDF) of Al–20 wt-% Si alloys with the addition of refiners and modifiers. The MDF process was performed at 200°C with a cumulative strain of 0.63. Microstructural characterization and mechanical performance were evaluated on the Al–20Si, Al–20Si–4.5Cu, Al–20Si–4.5Cu–1(Al–Ti–B), Al–20Si–4.5Cu–1(Al–Ti–B)–10(Al–Sr). The microstructure analysis revealed significant changes in the eutectic and primary phase refinement. The micro-Vickers hardness confirmed that the MDF process resulted in increased hardness (125 ± 1.9 VHN) compared to the homogenized samples (96 ± 2.7 VHN). Tensile test results showed that with the accumulation of strain, ultimate tensile strength increased to 435 MPa from 302 MPa with reduction in the percentage of elongation from 7.8 to 5.6. The grains were more uniformly distributed with addition of modifiers, and refiners further reduced the nucleation number of eutectic grains. The wear study demonstrated that the wear resistance is more in the Al–Si-Cu-Sr sample due to the increased level of hardness. The combination of multidirectional forging techniques with judicious incorporation of refiners and modifiers engenders a synergistic enhancement of microstructural integrity, hardness profiles, and wear-resistant properties in hypereutectic Al-20Si alloys. © 2024 Canadian Institute of Mining, Metallurgy and Petroleum.