Role of Recrystallized Grains on the Environment-Assisted Cracking of Aluminium-Alloy

2013 ◽  
Vol 753 ◽  
pp. 489-492
Author(s):  
M. Bobby Kannan
Keyword(s):  
Heat Treatment ◽  
Grain Boundary ◽  
Strain Rate ◽  
Aluminium Alloy ◽  
High Strength ◽  
Test Methods ◽  
Aged Alloy ◽  
Rate Testing ◽  
Peak Aged

In this study, the role of recystrallized grains on the environment-assisted cracking (EAC) susceptibility of a high strength aluminium alloy (Al-Zn-Mg-Cu) was examined using slow strain rate testing (SSRT) and U-bend test methods in chloride-containing solution. Experimental results suggest that the recrystallized grains in the peak-aged alloy are more prone to EAC. However, by altering the morphology and chemistry of the grain boundary precipitates of the recrystallized grains by overaging heat treatment, the alloy susceptibility to EAC reduced significantly.

Enhancing the Localized Corrosion Resistance of High Strength 7010 Al-Alloy

2010 ◽  
Vol 138 ◽  
pp. 1-6 ◽  
Author(s):  
M. Bobby Kannan ◽  
V.S. Raja
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Grain Boundary ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Intergranular Corrosion ◽  
High Strength ◽  
Localized Corrosion ◽  
Al Alloy

This paper brings out the developments on heat-treatment and alloying to improve the stress corrosion cracking (SCC) behavior of 7010 Al-alloy. The role of microstructures including the grain boundary precipitates and recystallized grains and the relation of intergranular corrosion (IGC) on the SCC behavior of 7010 Al-alloy have been discussed.

Strain-induced martensite effects on transgranular carbide precipitation in type 304 stainless steels

1991 ◽  
Vol 49 ◽  
pp. 604-605
Author(s):  
A.H. Advani ◽  
L.E. Murr ◽  
D. Matlock
Keyword(s):  
Heat Treatment ◽  
Grain Boundary ◽  
Stress Corrosion Cracking ◽  
Stainless Steels ◽  
Deformation Twin ◽  
Austenitic Stainless Steels ◽  
Carbide Precipitation ◽  
Strain Induced Martensite ◽  
Type 304

Thermomechanically induced strain is a key variable producing accelerated carbide precipitation, sensitization and stress corrosion cracking in austenitic stainless steels (SS). Recent work has indicated that higher levels of strain (above 20%) also produce transgranular (TG) carbide precipitation and corrosion simultaneous with the grain boundary phenomenon in 316 SS. Transgranular precipitates were noted to form primarily on deformation twin-fault planes and their intersections in 316 SS.Briant has indicated that TG precipitation in 316 SS is significantly different from 304 SS due to the formation of strain-induced martensite on 304 SS, though an understanding of the role of martensite on the process has not been developed. This study is concerned with evaluating the effects of strain and strain-induced martensite on TG carbide precipitation in 304 SS. The study was performed on samples of a 0.051%C-304 SS deformed to 33% followed by heat treatment at 670°C for 1 h.

Tensile Behaviour of 6082 Aluminium Alloy Sheet under Different Conditions of Heat Treatment, Temperature and Strain Rate

2009 ◽  
Vol 423 ◽  
pp. 105-112 ◽  
Author(s):  
I. Torca ◽  
A. Aginagalde ◽  
J.A. Esnaola ◽  
L. Galdos ◽  
Zigor Azpilgain ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Strain Rate ◽  
Aluminium Alloy ◽  
Aluminium Alloys ◽  
Room Temperature ◽  
Microstructural Analysis ◽  
Weight Ratio ◽  
Alloy Sheet ◽  
Treatment Temperature ◽  
Tensile Behaviour

Aluminium alloys are more and more important for the automotive industry due to their high strength to weight ratio and their elevated ductility; they are used for many different parts in automobiles as exterior panels, structural parts, brake housings and others. However, their formability at room temperature is limited. This inconvenient can be improved by increasing the forming temperature of the part. That lack of formability has lead to this research project dealing with the tensile behaviour of aluminium alloys sheets, at different conditions of temperature and strain rate. The analyzed material has been 6082 aluminium alloy, under two different heat treatment conditions (O and T6). Material testing has been carried out in a temperature range between room temperature and 250°C, and a strain rate range between 0.001s-1 and 0.1s-1. Testing samples have been obtained from laminated sheet of 1.5mm thickness. This article shows that the alloy under T6 condition has a reduced formability, even in warm conditions. In order to get higher deformation values an annealed condition is proposed to form the material. The effect of T6 heat treatment and O annealing treatment in the uniaxial warm formability is discussed and a microstructural analysis is also presented in order to understand the differences on the alloy behaviour.

Microstructure Evolution of Mg-10Gd-2Y-0.5Zn-0.3Zr Alloy during Isothermal Forging Process

2014 ◽  
Vol 783-786 ◽  
pp. 485-490
Author(s):  
De Bin Shan ◽  
X.Z. Han ◽  
Wen Chen Xu
Keyword(s):  
Microstructure Evolution ◽  
Ageing Time ◽  
High Strength ◽  
Aged Alloy ◽  
Secondary Phases ◽  
Obvious Effect ◽  
Isothermal Forging ◽  
Forging Process ◽  
The Matrix ◽  
Peak Aged

The isothermal forging process of a bracket and its microstructure evolution of Mg-10Gd-2Y-0.5Zn-0.3Zr alloy have been investigated in the present study. The results show that the bracket with thin-web and high-rib is well formed through modifying corners and adding an active damping block into male die. Amounts of lamellae and particles distribute uniformly on the matrix after the isothermal forging process and ageing process. The isothermal forging process has an obvious effect on the precipitation behaviour of secondary phases, while it did not change the grain size greatly. With the increase of ageing time, more secondary phases precipitate from α-Mg matrix until 60h. The optimal ultimate tensile strength and elongation of the peak-aged alloy are 382MPa and 4.03%, respectively. The combined effects of LPO and β′ phases contribute to the high strength of the peak-aged alloy.

Effect of Isothermal Heat Treatment on Dynamic Properties of a High Strength Steel

2015 ◽  
Vol 782 ◽  
pp. 124-129
Author(s):  
Wen Wen Du ◽  
Qian Wang ◽  
Lin Wang ◽  
Ding Wang
Keyword(s):  
Heat Treatment ◽  
Yield Strength ◽  
Strain Rate ◽  
High Strength Steel ◽  
Split Hopkinson Pressure Bar ◽  
Testing Machine ◽  
High Strength ◽  
Isothermal Heat Treatment ◽  
Quenching Temperature ◽  
Isothermal Temperature

The high strength steel which was subjected with isothermal heat treatment at three different temperatures, namely 330°C, 350°Cand 380°C after different quenching temperature namely 880°C and 900°C,was investigated in this paper. The quasi-static and dynamic mechanical properties of new high strength steel was tested by universal material testing machine and Split Hopkinson Pressure Bar (SHPB). Experimental results have showed that the yield strength and tensile strength of the steel reach 1100MPa and 1400MPa respectively. Hardness, yield strength and toughness are found to decrease with the consequently increasing of isothermal temperature under the same quenching temperature. The compression properties of the steel under quenching temperature of 880°C are higher than that of 900°C with the same isothermal temperature. It can be found that the steel which is subjected with isothermal heat treatment show strain rate sensitivity under high velocity impact. When isothermal temperature is set 380°C, the steel exhibits the most obvious strain rate hardening effect.

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