Welding Metallurgy of

With the presentation of a theory of liquid alloys, we have now assembled all the necessary tools for the ab initio construction of an alloy phase diagram.

Alloy Phase Diagrams

Recent progress on control strategies for inherent issues in friction stir welding

Methods of deforming metals to large strains are reviewed and the process of equal channel angular extrusion is analysed in detail. The development of microstructure during large strain deformation is discussed, and it is concluded that the main criterion for the formation of a sub–micron grain structure is the generation of a sufficiently large fraction (> 0.7) of high–angle grain boundary during the deformation process. For aluminium alloys, it is found that a low–temperature anneal is required to convert the deformed microstructure into an equi–axed grain structure. The material, microstructural and processing factors that influence the formation of such fine–grain microstructures are discussed, and the stability of these microstructures at elevated temperatures is considered.

Developing stable fine-grain microstructures by large strain deformation - Discussion

Friction Stir Welding(摩擦撹拌接合)法の熱工学的研究

The effect of substrate's heat treatment on microstructural and mechanical evolution of transient liquid phase bonded IN-738 LC

Effect of second-phase particle size and presence of vibration on AZ91/SiC surface composite layer produced by FSP

In this study, the dissimilar friction stir welding (FSW) butt joints between aluminum alloy 5754-H114 and commercially pure copper were investigated. The thickness of welded plates was 4 mm and the aluminum plate was placed on the advancing side. In order to obtain a suitable flow and a better material mixing, a 1-mm offset was considered for the aluminum plate, toward the butt centerline. For investigating the microstructure and mechanical properties of FSWed joints, optical microscopy and mechanical tests (i.e., uniaxial tensile test and microhardness) were used, respectively. Furthermore, the analysis of intermetallic compounds and fracture surface was examined by scanning electron microscopy and X-ray diffraction. The effect of heat generation on the mechanical properties and microstructure of the FSWed joints was investigated. The results showed that there is an optimum amount of heat input. The intermetallic compounds formed in FSWed joints were Al4Cu9 and Al2Cu. The best results were found in joints with 1000 rpm rotational speed and 100 mm/min travel speed. The tensile strength was found as 219 MPa, which reached 84% of the aluminum base strength. Moreover, maximum value of the microhardness of the stir zone (SZ) was attained as about 120 HV, which was greatly depended on the grain size, intermetallic compounds and copper pieces in SZ.

Seyyed Ehsan Mirsalehi

Papers

The effect of substrate's heat treatment on microstructural and mechanical evolution of transient liquid phase bonded IN-738 LC

Effect of second-phase particle size and presence of vibration on AZ91/SiC surface composite layer produced by FSP

Dissimilar Joining of Pure Copper to Aluminum Alloy via Friction Stir Welding

Vacuum TLP bonding of Inconel 617 superalloy using Ni-Cr-Si-Fe-B filler metal: Metallurgical structure and mechanical properties

Effect of pin penetration depth on double-sided friction stir welded joints of AA6061-T913 alloy