THE APPLICATION OF FRICTION STIR PROCESSING TO THE FABRICATION OF MAGNESIUM-BASED FOAMS

In the present paper, friction stir processing (FSP) is used to fabricate magnesium-based nanocomposite foams. The effects of the number of FSP passes, TiH2 to Al2O3 weight ratio, and foaming temperature; on the pore distribution and porosity are described. The results indicate that a minimum TiH2 to Al2O3 weight ratio is necessary to provide the best pore distribution and porosity. Closed-cell porous magnesium with a porosity of about 17.5% was successfully fabricated using 4-pass FSP at 800 rpm, by adding 5 mass% TiH2 and 3.5 mass% Al2O3; at a holding temperature of 858 K, and a holding time of 45 min.111Ysciescopu

A novel approach for producing in situ Al-Al2Cu composite via friction stir processing

In situ Al-Al2Cu surface composites were synthesized via friction stir processing (FSP) at aluminium plate with brass foil interlayer(s). The effects of rotational speed, number of FSP passes, and number of brass interlayers were investigated. Defect-free surface composites with the Al2Cu particles were successfully produced in all the processed FSP conditions. The surface composites consisted of a fine grained aluminium matrix (2-10 mu m), Al2Cu particles and some unreacted brass fragments remain mainly at the bottom of the stir zone. An improvement in hardness (up to 300%) compared with the aluminum base metal was achieved. Also, the activation energy and diffusion pre-factor of Al2Cu phase produced by FSP were estimated.11Nsciescopu

Fabrication of Al/Al2Cu in situ nanocomposite via friction stir processing

The aim of present work is fabrication of Al/Al2Cu in situ nanocomposite by friction stir processing (FSP) as well as investigation of FPS parameters such as rotational speed, travel speed, number of FSP passes, and pin profile on the microstructure, chemical reaction, and microhardness of Al based nanocomposite. The Al2Cu particles were formed rapidly due to mechanically activated effect of FSP as well as high heat generation due to Al-Cu exothermic reaction. The microstructure of the nanocomposites consisted of a finer grained aluminium matrix (��15 ?m), unreacted Cu nanoparticles (��40 nm), and reinforcement nanoparticles of Al2Cu. Irregular morphology of Al2Cu is attributed to the local melting during FSP. Pin diameter has a higher effect on the microstructure and hardness values. The hardness measurements exhibited enhancement by 57% compared with the base metal. ? 2017 The Nonferrous Metals Society of China116sciescopu

Mechanical properties and microstructural evaluation of AA1100 to AZ31 dissimilar friction stir welds

In this paper, microstructure and mechanical properties of dissimilar friction stir welds of AA1100 and AZ31 were investigated to understand the effects of rotational and travel speed as well as pin position. The tensile results of welded samples revealed that the sound welds were formed when the stirring pin deviated from the centreline to the AZ31 side. The X-ray diffraction shows that Al3Mg2 and Ah(12)Mg(17) intermetallics formation occurs in the stir zone during the welding process. High hardness of these intermetallic phases increased the hardness of the stir zone to 110 Hv. The best tensile results were obtained in the sample processed in the range of 28-32 (rev/mm) rotational to travel speed ratio. (C) 2015 Elsevier B.V. All rights reserved.1174sciescopu

Characterizations of dissimilar friction welding of ST37 and CK60 steels

The aim of the current work is to study the effect of friction welding parameters such as joint design and rotational speed on the microstructure and mechanical properties of ST37 steel to CK60 steel joints. The tensile strength of the joints was determined using notch tensile tests. The hardness was measured across and perpendicular to the interface. Weld toughness was measured using Charpy impact tests. The results of notch tensile tests indicate that the strength of the weld zone is between those of the two components. The toughness of the weld zone was lower than both base materials. The fracture surface showed cleavage features. The round head samples had better results than for the flat ones.1121sciescopu

Effect of friction stir processing on the microstructure of pure magnesium castings

In this paper, the effects of the pin profile and its rotational speed on material flow, microstructure, hardness and grain orientation of the friction-stirred pure Mg castings were investigated. For this purpose, three different tool pin profiles (non-threaded cylindrical, threaded cylindrical and conical) were used with various tool rotational speeds. The material flow, refining and grain growth of the material during the friction stir processing was monitored and then related to the Zener-Hollomon parameter. The grain orientation distribution was also investigated using X-ray diffraction.1112sciescopu

The Application of Friction Stir Processing to the Fabrication of Magnesium-Based Foams

In the present paper, friction stir processing (FSP) is used to fabricate magnesium-based nanocomposite foams. The effects of the number of FSP passes, TiH2 to Al2O3 weight ratio, and foaming temperature; on the pore distribution and porosity are described. The results indicate that a minimum TiH2 to Al2O3 weight ratio is necessary to provide the best pore distribution and porosity. Closed-cell porous magnesium with a porosity of about 17.5% was successfully fabricated using 4-pass FSP at 800 rpm, by adding 5 mass% TiH2 and 3.5 mass% Al2O3; at a holding temperature of 858 K, and a holding time of 45 min

FABRICATION OF AZ31/Al(2)O(3) NANOCOMPOSITES BY FRICTION STIR PROCESSING

The aim of this paper is to fabricate AZ31/Al2O3 nanocomposites by friction stir processing (FSP). Due to severe plastic deformation, dynamic recrystallization, and grain growth retardation by nanoparticles during the FSP processing, ultrafine grained microstructures with homogeneous distribution of the nanoparticles were produced. With increasing rotational speed, as a result of the increased plastic deformation and heat generation, increased grain size of the matrix, and simultaneously shattering effect of rotation cause a uniform nanoparticle distribution. By the large plastic deformation, texture of the matrix evolved and especially the (0002) basal plane was developed.X115sciescopu