Superplastic Deformation and Microstructure Evolution of Friction Stir Weld of 1420 Al-Li Alloy

2005 ◽  
Vol 475-479 ◽  
pp. 3033-3036 ◽  
Author(s):  
He Ping Guo ◽  
Xiu Quan Han ◽  
Wei Wu ◽  
Zhi Qiang Li

Friction stir welding is a novel welding technique which has been successfully applied in structure manufacturing of aluminium alloys (including 2XXX and 7XXX). Friction stirring in aluminium alloy welds produces a combination of very fine grain size. This paper deals with the SPF response in 1420 Al-Li alloy welds. The results showed that the friction stir weld could achieve good superplasticity performance. The lateral elongation in the weld could reach 120% and the grain size still remain the same size with little change. And the drawback in the friction weld is the obstacle to fufill the good SPF ability. During the friction stir welding, some oxides or contaminates were stired into the weld in the form of black line. When the weld was experienced superplastic deformation, the crack initiated from the line and finally reach the surface and bottom of the plate. The oxide was formed mainly in the nugget of the friction weld. So the parameters and preparation before welding must be optimized so that the weld can achieve maximum superplasticity performance.

2010 ◽  
Vol 638-642 ◽  
pp. 1179-1184 ◽  
Author(s):  
Philip L. Threadgill ◽  
M.M.Z. Ahmed ◽  
Jonathan P. Martin ◽  
Jonathan G. Perrett ◽  
Bradley P. Wynne

The use of a double sided friction stir welding tool (known as a bobbin tool) has the advantage of giving a processed zone in the workpiece which is more or less rectangular in cross section, as opposed the triangular zone which is more typically found when conventional friction stir welding tool designs are used. In addition, the net axial force on the workpiece is almost zero, which has significant beneficial implications in machine design and cost. However, the response of these tools in generating fine microstructures in the nugget area has not been established. The paper presents detailed metallographic analyses of microstructures produced in 25mm AA6082-T6 aluminium wrought alloy, and examines grain size, texture and mechanical properties as a function of processing parameters and tool design, and offers comparison with data from welds made with conventional tools.


2021 ◽  
Vol 2021 ◽  
pp. 1-21
Author(s):  
A. Praveen Raj Navukkarasan ◽  
K. Shanmuga Sundaram ◽  
C. Chandrasekhara Sastry ◽  
M. A. Muthu Manickam

An attempt has been made to investigate dry and cryogenic friction stir welding of AA 7075 aluminium alloy, which is predominantly availed in aerospace and defence component industries. These industries avail friction stir welding for joining two nonferrous materials, and minimal deviations and maximum strength are the preliminary and long time goal. A cryogenic friction stir welding setup was developed to conduct the joining of two aluminium alloy pipes. An increase of 0.76–42.93% and 3.79–31.24% in microhardness and tensile strength, respectively, is ascertained in cryogenic friction stir welding in correlation to dry friction stir welding of aluminium alloys. TOPSIS evaluation for the experimental run indicated tool profile stepped type, pipe rotation speed of 1000 rpm, welding speed of 50 mm/min, and axial force of 8 kN as close to unity ideal solution for dry and cryogenic friction stir welding of AA 7075 aluminium alloys. The friction stir-welded component under the cryogenic environment showcased drop in temperature, curtailed surface roughness, and fine grain structure owing to reduction in temperature differential occurring at the weld zone. A curtailment of 50.84% is ascertained in the roughness value for cryogenic friction stir welding in correlation to dry friction stir welding of AA 7075 alloy. A decrement of 21.68% is observed in the grain size in the cryogenic condition with correlation to the dry FSW process, indicating a drop in the coarse structure. With the curtailment of grain size and drop in temperature differential, compressive residual factor and corrosion resistance attenuated by 40.14% and 67.17% in the cryogenic FSW process in correlation to the dry FSW process, respectively.


Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 214 ◽  
Author(s):  
Velaphi Msomi ◽  
Nontle Mbana

Welding of dissimilar aluminium alloys has been a challenge for a long period until the discovery of the solid-state welding technique called friction stir welding (FSW). The discovery of this technique encouraged different research interests revolving around the optimization of this technique. This involves the welding parameters optimization and this optimization is categorized into two classes, i.e., similar alloys and dissimilar alloys. This paper reports about the mechanical properties of the friction stir welded dissimilar AA1050-H14 and AA5083-H111 joint. The main focus is to compare the mechanical properties of specimens extracted from different locations of the welds, i.e., the beginning, middle, and the end of the weld. The specimen extracted at the beginning of the weld showed low tensile properties compared to specimens extracted from different locations of the weld. There was no certain trend noted through the bending results. All three specimens showed dimpled fracture, which is the characterization of the ductile fracture.


Author(s):  
Velaphi Msomi ◽  
Nontle Mbana

Welding of dissimilar aluminium alloys has been a challenge for a long period until the discovery of the solid state welding technique called friction stir welding (FSW). The discovery of this technique encouraged different research interests revolving around the optimization of this technique. This involves the welding parameters optimization and this optimization is categorized into two classes i.e. similar alloys and dissimilar alloys. This paper reports about the mechanical properties of the friction stir welded dissimilar AA1050-H14 and AA5083-H111 joint. The main focus is to compare the mechanical properties of specimens extracted from different locations of the welds i.e. the beginning, middle and the end of the weld. The specimen extracted at the beginning of the weld showed low tensile properties compared to specimens extracted from different locations of the weld. There was no certain trend noted through the bending results. All three specimens showed dimpled fracture which is the characterization of the ductile fracture.


Author(s):  
A.A. Saleh

Purpose: This work aims to investigate the microstructure and mechanical properties achieved by FSW of butt joints, namely of dissimilar sheets namely of 2014-T3 to 5059-H11 Al alloys by bonding the two materials perpendicular to their rolling directions. Design/methodology/approach: AA 2014T3 and AA 5059H11 were two dissimilar aluminium alloys friction stir welded. The joint has been examined in terms of hardness, microstructure, and mechanical properties. The microstructure of the weld area was characterized by using optical microscopy. Seven diverse regions of the microstructure in the joint can be illustrious. Findings: It has been noticed that a structure of fine grain is formed in the nugget region as a consequence of recrystallization. The thermos mechanically affected and heat affected zones of aluminium alloy 2014 are characterized by the lowest hardness values in spite of there are a general hardness decrease through the weld zone compared to both base metals. The ultimate tensile strength values of the dissimilar joint were found to be varying between 54% to 66% those of the base metal. Research limitations/implications: The t joining in FSW takes place with the base materials remnant in the solid state, which gives a considerable possibility to produce joints between the alleged difficult-to-weld heat treatable aluminium alloys. Originality/value: The outcomes display that friction stir welding can be effectively applied for the joining of dissimilar aluminium alloys.


Author(s):  
Sanjeev Verma ◽  
Vinod Kumar

Aluminium and its alloys are lightweight, corrosion-resistant, affordable and high-strength material and find wide applications in shipbuilding, automotive, constructions, aerospace and other industrial sectors. In applications like aerospace, marine and automotive industries, there is a need to join components made of different aluminium alloys, viz. AA6061 and AA5083. In this study friction stir welding (FSW) is used to join dissimilar plates made of AA6061-T6 and AA5083-O. The effect of varying tool pin profile, tool rotation speed, tool feed rate and tilt angle of the tool has been investigated on the tensile strength and percentage elongation of the welded joints. Box-Behkan design, with four input parameters and three levels of each parameter has been employed to decide the set of experimental runs. The regression models have been developed to investigate the influence of welding variables on the tensile strength and elongation of the welded joint. It is revealed that with the increase in welding parameters like tool rpm, tool feed rate and tilt angle of the tool, both the mechanical properties increase, reach a maximum level, followed by a decrease with further increase in the value of parameters. Amongst different types of tool pin profiles used, the FSW tool having straight cylindrical (SC) pin profile is found to yield the maximum strength and elongation of the welded joint for different combinations of welding parameters. Multiple response optimization indicates that the maximum UTS (135.83 MPa) and TE (4.35%) are obtained for the welded joint fabricated using FSW tool having SC pin profile, tilted at 1.11° and operating at tool speed and feed rate of 1568 rpm and 39.53 mm/min., respectively.


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