Fatigue of Unmachined Aluminium Alloy Extrusions

1962 ◽  
Vol 13 (3) ◽  
pp. 271-274 ◽  
Author(s):  
K. W. Gunn ◽  
A. R. Woodward
Keyword(s):  
Laboratory Test ◽  
Aluminium Alloy ◽  
Shot Peening ◽  
Copper Alloys ◽  
High Strength ◽  
Fatigue Properties ◽  
Test Pieces ◽  
Compressive Stresses ◽  
Aluminium Copper ◽  
Effect Of Surface

SummaryThe fatigue properties of unmachined extrusions of high-strength aluminium-copper alloys are known to be lower than those of conventional fully-machined test pieces. Work described in this note has shown that the removal of a layer of metal 0·025 in. thick from the surface of B.S. L65-type extrusions results in an increase in fatigue properties to values approaching those obtained from the conventional laboratory test pieces. Because the removal of material from the surface is not always a practical proposition, other methods of improving strength have been examined and the effect of surface compressive stresses has been shown to be beneficial. Sufficient compressive stress can be induced by surface-rolling to increase the fatigue properties to those of conventional specimens, but this method can only be easily applied to round sections and it is suggested that shot-peening or vapour-blasting could be used for more complicated sections.

scholarly journals Effect of shot peening on fatigue properties of high strength Al alloy in high humidity

2015 ◽  
Vol 81 (825) ◽  
pp. 15-00001-15-00001
Author(s):  
Norio KAWAGOISHI ◽  
Kohji KARIYA ◽  
Takanori NAGANO ◽  
Qiang CHEN ◽  
Qingyuan WANG ◽  
...  
Keyword(s):  
Shot Peening ◽  
High Strength ◽  
Fatigue Properties ◽  
Al Alloy ◽  
High Humidity

scholarly journals Influences of Horizontal and Vertical Build Orientations and Post-Fabrication Processes on the Fatigue Behavior of Stainless Steel 316L Produced by Selective Laser Melting

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4203 ◽  
Author(s):  
Paul Wood ◽  
Tomasz Libura ◽  
Zbigniew L. Kowalewski ◽  
Gavin Williams ◽  
Ahmad Serjouei
Keyword(s):  
Stainless Steel ◽  
Selective Laser Melting ◽  
Shot Peening ◽  
Fatigue Behavior ◽  
Fracture Pattern ◽  
Fatigue Properties ◽  
Stainless Steel 316L ◽  
Laser Melting ◽  
Test Pieces ◽  
Laser Systems

In this paper, the influences of build orientation and post-fabrication processes, including stress-relief, machining, and shot-peening, on the fatigue behavior of stainless steel (SS) 316L manufactured using selective laser melting (SLM) are studied. It was found that horizontally-built (XY) and machined (M) test pieces, which had not been previously studied in the literature, in both stress-relieved (SR) or non-stress-relieved (NSR) conditions show superior fatigue behavior compared to vertically-built (ZX) and conventionally-manufactured SS 316L. The XY, M, and SR (XY-M-SR) test pieces displayed fatigue behavior similar to the XY-M-NSR test pieces, implying that SR does not have a considerable effect on the fatigue behavior of XY and M test pieces. ZX-M-SR test pieces, due to their considerably lower ductility, exhibited significantly larger scatter and a lower fatigue strength compared to ZX-M-NSR samples. Shot-peening (SP) displayed a positive effect on improving the fatigue behavior of the ZX-NSR test pieces due to a compressive stress of 58 MPa induced on the surface of the test pieces. Fractography of the tensile and fatigue test pieces revealed a deeper understanding of the relationships between the process parameters, microstructure, and mechanical properties for SS 316L produced by laser systems. For example, fish-eye fracture pattern or spherical stair features were not previously observed or explained for cyclically-loaded SLM-printed parts in the literature. This study provides comprehensive insight into the anisotropy of the static and fatigue properties of SLM-printed parts, as well as the pre- and post-fabrication parameters that can be employed to improve the fatigue behavior of steel alloys manufactured using laser systems.

scholarly journals Review on Multi-Pass Friction Stir Processing of Aluminium Alloys

2020 ◽  
Author(s):  
Oritonda Muribwathoho ◽  
Sipokazi Mabuwa ◽  
Velaphi Msomi
Keyword(s):  
Friction Stir Processing ◽  
Aluminium Alloys ◽  
Weight Ratio ◽  
High Strength ◽  
Fatigue Properties ◽  
Dissimilar Metals ◽  
Friction Stir ◽  
Aluminium Copper ◽  
The Impact ◽  
Welding Technique

Aluminium alloys have evolved as suitable materials for automotive and aircraft industries due to their reduced weight, excellent fatigue properties, high-strength to weight ratio, high workability/formability, and corrosion resistance. Recently, the joining of similar and dissimilar metals have achieved huge success in various sectors. The processing of soft metals like aluminium, copper, iron and nickel have been fabricated using friction stir processing. Friction stir processing (FSP) is a microstructural modifying technique that uses the same principles as the friction stir welding technique. In the majority of studies on FSP, the effect of process parameters on the microstructure was characterized after a single pass. However, multiple passes of FSP is another method to further modify the microstructure in aluminium castings. This study is aimed at reviewing the impact of multi-pass friction stir processed joints of aluminium alloys and to identify a knowledge gap. From the literature that is available on multi-pass FSP, it has been observed that the majority of the literature focused on the processing of plates than the joints. There is limited literature reporting on multi-pass friction stir processed joints. This then creates a need to study further on multi-pass friction stir processing on dissimilar aluminium alloys.

The Effect of Surface Over-Aging on the Strength and SCC Susceptibility of 7075 Aluminum Alloy

2009 ◽  
Author(s):  
Hamidreza Fooladfar ◽  
Babak Hashemi ◽  
Mousa Younesi
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Shot Peening ◽  
High Strength ◽  
7075 Aluminum Alloy ◽  
Treatment Procedure ◽  
Aging Period ◽  
Two Stages ◽  
Heat Treatment Procedure ◽  
Effect Of Surface

A novel heat treatment procedure combining the shot-peening with a two-step aging operation was proposed to improve both the strength and the stress corrosion cracking (SCC) resistance of the high-strength 7075 aluminium alloy. The heat treatment included one shot-peening stage before or between the two stages of aging at 120°C for 24 h and at 160°C for 1 h, respectively. The mechanical properties obtained during the aforementioned operations were extremely similar to those of the T6 sample owing to the unaffected bulk microstructure over such a low over-aging period. The SCC resistance of these samples was considerably improved, compared to that of the T6 sample and of the conventional shot-peened T6 sample due to the over-aging of the surface like the T7 treatment leading from the diffusion acceleration by the dislocations generated in the surface layer during shot-peening. In spite of the further depth of deformation caused by shot-peening prior to the first step of aging, the sample shot-peened after the first step of aging showed no significant decrease in the SCC resistance because of its higher generated dislocation by shot-peening.

Mechanical and fatigue properties of self-piercing riveted joints in high-strength steel and aluminium alloy

2017 ◽  
Vol 24 (2) ◽  
pp. 214-221 ◽  
Author(s):  
Chun-yu Zhang ◽  
Rui-bin Gou ◽  
Min Yu ◽  
Ya-jing Zhang ◽  
Yin-hu Qiao ◽  
...  
Keyword(s):  
Aluminium Alloy ◽  
High Strength Steel ◽  
High Strength ◽  
Fatigue Properties ◽  
Riveted Joints

The Fatigue Properties of Z-Section Test Pieces Completely Machined from an Aluminium Alloy Extrusion Conforming to D.T.D. 364B

1953 ◽  
Vol 57 (506) ◽  
pp. 103-107 ◽  
Author(s):  
G. Forrest ◽  
K. W. Gunn ◽  
A. R. Woodward
Keyword(s):  
Aluminium Alloy ◽  
Fatigue Test ◽  
Fatigue Properties ◽  
Test Results ◽  
Axial Loads ◽  
Testing Technique ◽  
Great Caution ◽  
Test Pieces ◽  
Round Bar ◽  
Bar Test

In 1949 F. H. Pollicutt, in the course of a discussion on a paper presented by P. B. Walker to the Royal Aeronautical Society, reported fatigue test results which indicated that when the aluminium alloy conforming to specification D.T.D.364 was tested, under , axial loads, in the form of Z-sections, its fatigue properties were extremely low. Z-sections with unmachined surfaces and even Z-sections with completely machined surfaces failed after short endurances at stress ranges under which small polished round test pieces would not have failed even after hundreds of millions of cycles. Pollicutt, in discussing these low values, advised that great caution should be exercised in their interpretation, warning equally against an unqualified acceptance of the testing technique and a too facile acceptance of small polished round bar test results.

Influence of Shot Peening on Fatigue Properties in Ultra-High Strength Steels

2005 ◽  
Vol 490-491 ◽  
pp. 448-453 ◽  
Author(s):  
Yu Kui Gao ◽  
Xue Ren Wu ◽  
Feng Lu ◽  
Mei Yao ◽  
Qingxian Yan
Keyword(s):  
Residual Stress ◽  
Fatigue Crack ◽  
Fatigue Limit ◽  
Surface Integrity ◽  
Shot Peening ◽  
Fatigue Crack Initiation ◽  
High Strength Steels ◽  
High Strength ◽  
Fatigue Properties ◽  
Ultra High Strength Steels

The characteristics of compressive residual stress fields induced by shot peening in 40CrNi2Si2MoVA, 16Co14Ni10Cr2Mo, 30CrMnSiNi2A and 0Cr13Ni8Mo2Al ultra-high strength steels, which are used widely in aeronautical industry were investigated, and the change of surface integrity including surface residual stress, surface roughness as well as its effects on fatigue properties were investigated. The results show that the fatigue limits of ultra-high strength steels can be increased by shot peening because the surface integrity can be ameliorated by shot peening, and that for a given steel there is a appropriate peening intensity under which the fatigue property of this steel is optimum. Finally, a judgement for the optimization condition of shot peening process is proposed based on a theory of micro-meso processes of fatigue crack initiation and experimental results. The technique should be considered to be optimum, if the fatigue crack source of shot peened specimen has been moved to the internal matrix metal region beneath the hardened layer; and its apparent fatigue limit has been improved and got to a value, which is near to that predicted according to the concept of surface/internal fatigue limit.

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