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Enhancement of mechanical properties and wear of AA5083/316 stainless steel surface-composite developed through multi-pass friction stir processing (MPFSP)

Yang Yiran, Paidar Moslem, Mehrez Sadok, Ojo Olatunji Oladimeji

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 1

art. no. e13, 2023

EN

In this investigation, the AA5083/316 stainless steel (ss) surface composite was generated by the friction stir processing (FSP) with the aim of improving the mechanical properties, the corrosion and tribological performances of the composite. The FSP process was conducted at different tool pass numbers (1-P, 2-P, and 4-P) and a constant tool rotational (900 rpm) and travel (85 mm/min) speeds. To analyze the microstructure of the samples, optical (OM) and scanning electron microscopes (SEM) were employed to characterize the scattering of the 316 stainless steel (ss) particles within the AA5083 matrix. It was found that multi-pass FSP resulted in substantial grain refinement from 7.02 to 5.89 μm and better scattering of the reinforcement in the AA5083 Al matrix. Results also indicated that the mechanical and wear properties of the composite layers were enhanced by increasing the pass number from 1-pass to 4-pass, which can be credited to the formation of finer 316 stainless steel (ss) particles appropriately dispersed in the Al substrate. Furthermore, the results depicted that the corrosion resistance of the samples is enhanced with the increase of pass number.

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Friction spot extrusion brazing of copper to AISI 304 stainless steel with Zn interlayer: effect of shoulder surface modification

Bai Jing, Paidar Moslem, Mehrez Sadok, Ojo Olatunji Oladimeji, Nasution Mahyuddin Khairuddin Matyuso, Zain Azlan Mohd

Archives of Civil and Mechanical Engineering

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2022

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Vol. 22, no. 2

art. no. e62, 1--15

EN

The friction spot extrusion brazing of Cu and AISI 304 stainless plates was carried out with a pure Zn interlayer medium to prevent Cu-Fe reaction by changing the tool shoulder surfaces from smooth to scrolled shoulder. The metallurgical and mechanical characterizations and fracture behaviors of the as-welded joints were studied. The change in tool shoulder surface had no significant effect on the chemical composition and the formation of interlocked or the plastically deformed material flow zone of the joint at an unchanged processing parameter setting. The kernel average misorientation fraction, high angle grain boundaries, and dislocation density are slightly higher at the stir zone of the smooth shoulder-produced welds owing to the higher heat input in the scroll shoulder-produced counterparts. The change of the tool from a smooth shoulder to a scroll shoulder tool produced a slightly more flash (non-uniform), increased peak temperature (409-459°C), caused a rise in the average grains (6.58-7.73 μm) and promoted the fracture load (1359-2249 N) of the welds. Because there is no upper sheet bulging-induced interfacial gap at the brazed zone the tensile result of the scroll shoulder-produced joint has improved.

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Modified friction stir clinching-brazing of brass to AA5083 aluminum alloy using Zn interlayer

Li Jing, Tang Fei, Paidar Moslem

Archives of Civil and Mechanical Engineering

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2021

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Vol. 21, no. 1

219--229

EN

The modified friction stir clinching (MFSC) of 5083 aluminum alloy to brass using pure Zn interlayer has been explored and elucidated for the first time. By that, the influence of the Zn interlayer thickness on the microstructure and the mechanical properties of the 5083/brass joint was investigated. The attained data have revealed that the intermetallic compound (IMC) layer thickness was mainly influenced by the Zn interlayer. The use of the Zn interlayer restrained the creation of brittle Al–Cu IMCs such as Al4Cu9 during the MFSC process and, in return, softer phases such as Cu4Zn, CuZn5, and CuZn were formed. It was also found that with increasing the thickness of the Zn interlayer from 50 to 100 µm, the thickness of the brazed zone increased and the tensile/shear strength of the spot welds significantly improved from 5250 to 8490 N (approximately 60% increment over the welded sample with 50-µm-thick Zn) which can be ascribed to supreme bonding and homogeneous brazing zone at the interface.

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Investigation of modified friction stir clinching-brazing process of AA2024 Al/AZ31 Mg: metallurgical and mechanical properties

Paidar Moslem, Kazemi Amirreza, Mehrez Sadok, Ojo Olatunji Oladimeji, Nasution Mahyuddin Khairuddin Matyuso, Mironov Sergei Nikolaevich

Archives of Civil and Mechanical Engineering

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2021

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Vol. 21, no. 3

516--532

EN

The weldability of the AA2024-T3 and AZ31 Mg alloys was investigated using the modified friction stir clinching-brazing (MFSC-B) and probe-less friction stir spot brazing (PFSSB) processes. A 50 µm thick Zn foil-interlayer was sandwiched between the dissimilar base materials for the welding processes. The mechanical, microstructure, and weld-fracture behaviors of all joints were studied and compared. Zn-rich interdiffusion-aided lamellar and blocky structures are found at the brazed region/zone of the AA2024-T3/Zn/AZ31 joint irrespective of the welding process due to the sole influence of heat input at the zone. The differential flow in the MFSC-B joint enforces significant inter-material mingling, better distribution of Zn, and more subgrains/dislocation density at the joint as compared to the PFSSB joint. The interlayer inhibited the creation of the β-Al3Mg2 phase while the γ-Al12Mg17 phase could not be prevented in the AA2024-T3/Zn/AZ31 joints due to tool-induced atomic collision and diffusion–reaction mechanisms. Improved tensile/shear failure load is found in the MFSC-B joint (4369 N) as related to their PFSSB counterpart (3018 N) due to improved material flow (intermixing), and intense dislocation density. The MFSC-B process is thus recommended for dissimilar joining of Mg and Al alloys.