Initial holding time dependent warm deformation and post-ageing precipitation in an AA7075-T4 aluminum alloy

2021 ◽  
Vol 294 ◽  
pp. 117111
Author(s):  
Zhuangzhuang Feng ◽  
Chunhui Liu ◽  
Peipei Ma ◽  
Jianshi Yang ◽  
Kailiang Chen ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Holding Time ◽  
Time Dependent ◽  
Warm Deformation

scholarly journals The Effects of Creep on Elastic Modulus Measurement Using Nanoindentation

2000 ◽  
Vol 649 ◽  
Author(s):  
G. Feng ◽  
A.H.W. Ngan
Keyword(s):  
Elastic Modulus ◽  
Elastic Deformation ◽  
Elastic Moduli ◽  
Holding Time ◽  
Time Dependent ◽  
Nanoindentation Test ◽  
Modification Method ◽  
Unloading Rate ◽  
Modulus Measurement

ABSTRACTDuring the unloading segment of nanoindentation, time dependent displacement (TDD) accompanies elastic deformation. Consequently the modulus calculated by the Oliver-Pharr scheme can be overestimated. In this paper we present evidences for the influence of the measured modulus by TDD. A modification method is also presented to correct for the effects of TDD by extrapolating the TDD law in the holding process to the beginning of the unloading process. Using this method, the appropriate holding time and unloading rate can be estimated for nanoindentation test to minimise the effects of TDD. The elastic moduli of three materials computed by the modification method are compared with the results without considering the TDD effects.

Diffusion Bonding between AZ31 Magnesium Alloy and 7075 Aluminum Alloy

2014 ◽  
Vol 618 ◽  
pp. 150-153 ◽  
Author(s):  
Zhi Tong Chen ◽  
Fei Lin ◽  
Jie Li ◽  
Fei Wang ◽  
Qing Sen Meng
Keyword(s):  
Shear Strength ◽  
Aluminum Alloy ◽  
Magnesium Alloy ◽  
Diffusion Bonding ◽  
Holding Time ◽  
Az31 Magnesium Alloy ◽  
Diffusion Welding ◽  
7075 Aluminum Alloy ◽  
Micro Hardness ◽  
Welding Temperature

A study on vacuum diffusion bonding between as-extruded AZ31 magnesium alloy and 7075 aluminum alloy was carried out according to atomic diffusion theory. Recrystallization annealing was used for grain refinement of AZ31 magnesium alloy and 7075 aluminum alloy before the diffusion welding. The quality of the bonding joints was checked by shear test, micro-hardness test and microstructure analysis. Experimental results showed that the welding temperature and holding time have a great effect on the joint shear strength. The maximum of shear strength was 38.41MPa under the temperature of 470°C and the holding time of 60min. The result of micro-hardness measurement showed that the micro-hardness of welded joints was maximum. Three kinds of intermetallic compounds, Mg2A13, MgAl and Mgl7Al12, formed at the interfacial transition zone at 470°C.

Influence of Al-10RE Modification on Microstructure and Mechanical Properties of ZL203 Aluminum Alloy

2011 ◽  
Vol 365 ◽  
pp. 98-103
Author(s):  
De Quan Shi ◽  
Gui Li Gao ◽  
Zhi Wei Gao ◽  
Yan Liu Wang ◽  
Xu Dong Wang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Aluminum Alloy ◽  
Mechanical Testing ◽  
Testing Machine ◽  
Optical Microscope ◽  
Elongation Rate ◽  
Holding Time ◽  
Holding Temperature ◽  
Universal Mechanical Testing Machine

The influence of Al-10RE addition, holding time and holding temperature on the microstructures and mechanical properties of ZL203 aluminum alloy has been studied respectively through using the optical microscope and the universal mechanical testing machine. The experimental results lead to the following conclusions. When Al-10RE addition is 1.0%-1.5%, the holding time is 15 minutes and the holding temperature is 730°C-750°C, the microstructure of Zl203 is perfect. With the increase of Al-10RE addition, the mechanical properties including tensile strength, elongation rate and hardness gradually increase. When the Al-10RE addition is 1.0%-1.5%, the mechanical properties reaches maximum. When the Al-10RE addition is above 1.5%, the mechanical properties decrease with the increase of Al-10RE addition.

Study on Two-Step Aging Technology of 6082 Aluminum Bumper

2018 ◽  
Vol 764 ◽  
pp. 245-251
Author(s):  
Bei Ming Zhao ◽  
Miao Hu ◽  
Jun Zhu ◽  
Zhen Yu Han ◽  
Hou Qing Sun ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Process Parameters ◽  
Aging Temperature ◽  
Aging Process ◽  
Production Efficiency ◽  
Holding Time ◽  
Second Stage ◽  
Main Factors ◽  
6082 Aluminum Alloy

The influence of four parameters of two-step aging on the mechanical properties of 6082 aluminum alloy bumper was studied by orthogonal test. The results show that compared with the single stage aging, the two-step aging process can reduce the aging time and improve the production efficiency under the premise of the mechanical properties of the bumper meet the requirements. Among the four aging process parameters, the second stage aging temperature and holding time are the main factors that affect the final results, while the first stage aging temperature and holding time are secondary factors. The most suitable aging process parameters for the 6082 aluminum alloy bumper is (150 °C, 2 h) + (190 °C, 2.5 h). After two-step aging, the grain of the aluminum bumper is small and evenly distributed, leading to good mechanical properties. The generalized experiment shows that the application of the two-step aging process still has some limitations and needs to be further optimized and perfected.

Law of Crack Growth Life for P92 Steel Under the Conditions of Creep-Fatigue Multiplication and Projection of the Threshold Temperature of Creep Crack Growth Based on This Law

2009 ◽  
Author(s):  
A. T. Yokobori ◽  
R. Sugiura ◽  
S. Kimoto ◽  
D. Yoshino ◽  
T. Matsuzaki
Keyword(s):  
Crack Growth ◽  
Creep Crack Growth ◽  
Transition Function ◽  
Holding Time ◽  
Time Dependent ◽  
Threshold Temperature ◽  
P92 Steel ◽  
Operational Costs ◽  
Creep Fatigue ◽  
Heat Resistant Steels

W-added 9Cr ferritic heat-resistant steels, ASME grade P92, are used under the high temperature creep-fatigue condition. Concerning the maintenance of the operational safety and minimizing operational costs, it is necessary to construct a law of predicting the crack growth life by clarifying the dominant factors of the crack growth life under the condition of creep-fatigue multiplication (the effect of stress holding time on the time-dependent fracture). In this study, crack growth tests under the conditions of creep-fatigue multiplication were conducted with various conditions of stress holding time, applied stress and temperatures. As a result, a unified law of predicting the crack growth life under the conditions of creep-fatigue multiplication was derived based on the concept of Q* with the transition function of crack growth life from fatigue to creep.

Mechanical properties and creep behavior of lyocell fibers by nanoindentation and nano-tensile testing

Holzforschung ◽  
2007 ◽  
Vol 61 (3) ◽  
pp. 254-260 ◽  
Author(s):  
Seung-Hwan Lee ◽  
Siqun Wang ◽  
George M. Pharr ◽  
Matthew Kant ◽  
Dayakar Penumadu
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Tensile Testing ◽  
Holding Time ◽  
Time Dependent ◽  
Nanoindentation Test ◽  
Creep Equation ◽  
Mean Values ◽  
Significant Difference ◽  
Lyocell Fibers

Abstract Mechanical and time-dependent mechanical properties of lyocell fibers have been investigated as a function of depth at a nano-scale level in longitudinal and transverse directions. The nanoindentation technique was applied and extended to continuous stiffness measurement. Lyo10 and Lyo13 lyocell fibers were investigated. The individual fiber properties were measured using a nano-tensile testing system to obtain reference data for mechanical properties. The hardness and elastic modulus obtained from nanoindentation test are described using two different approaches. The first uses mean values for a depth of 150–300 nm, while the second uses unloading values at the final indentation depth. There is no significant difference between modulus values inferred from nanoindentation and those obtained from single fiber tensile testing. Hardness and elastic modulus values were higher in the longitudinal direction than those in the transverse direction and Lyo13 values were higher than those for Lyo10 in both directions. The time-dependent mechanical properties were also investigated as a function of the holding time. Increasing the holding time led to an increase in indentation displacement and a decrease in hardness. Stress exponents were calculated from the linear relationship between contact stress and contact strain using a power-law creep equation.

scholarly journals Effect of Semi-Solid Processing on the Microstructure and Mechanical Properties of Aluminum Alloy Chips with Eutectic Mg2Si Intermetallics

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1414
Author(s):  
Yong Guk Son ◽  
Sung Soo Jung ◽  
Yong Ho Park ◽  
Young Cheol Lee
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Eutectic Reaction ◽  
Microstructural Analysis ◽  
Aluminum Matrix ◽  
Processing Parameters ◽  
Holding Time ◽  
Mg2si Phase ◽  
Microstructure And Mechanical Properties ◽  
Semi Solid

This study reports the microstructural changes and mechanical properties of high-strength aluminum alloy chips prepared in the semi-solid state at different temperatures, pressures, and holding times. In semi-solid processes, these processing parameters must be optimized because they affect the microstructure and mechanical properties of the chips. In microstructural analysis, these parameters clearly influenced the spheroidization of the aluminum matrix. The aluminum matrix was uniformly spheroidized after semi-solid processing, and the densities of the final samples increased with the holding time. After 30 min holding time at a given temperature, the density approached the theoretical density, but the compressive strength of the samples seriously deteriorated. Meanwhile, fracture surface investigation revealed a deformed Mg2Si phase, which is formed through a eutectic reaction. The strength of this phase significantly decreased after increasing the holding time of the semi-solid processing from 10 to 30 min. Therefore, deformation of the Mg2Si phase caused by diffusion of aluminum into this phase can be a key factor for the decrease in the mechanical properties of samples fabricated with 30 min holding time.

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