Instantaneous plastic strain associated with stress changes during the steady state creep of Al and Al-4.20 at% Mg alloy

1985 ◽  
Vol 20 (3) ◽  
pp. 797-806 ◽  
Author(s):  
L. Moerner ◽  
D. O. Northwood ◽  
I. O. Smith
Keyword(s):  
Steady State ◽  
Plastic Strain ◽  
Steady State Creep ◽  
Mg Alloy ◽  
Stress Changes

scholarly journals Creep Mechanisms of an Al–Cu–Mg Alloy at the Macro- and Micro-Scale: Effect of the S′/S Precipitate

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2907 ◽  
Author(s):  
Yongqian Xu ◽  
Lingwei Yang ◽  
Lihua Zhan ◽  
Hailiang Yu ◽  
Minghui Huang
Keyword(s):  
Steady State ◽  
Steady State Creep ◽  
Creep Mechanism ◽  
Mg Alloy ◽  
Tensile Creep ◽  
Precipitate Size ◽  
Minor Role ◽  
Al Alloy ◽  
Creep Tests ◽  
Precipitate Growth

A novel methodology combining the macro- and micro-creep techniques was employed to study the effect of S′/S precipitate growth on the creep mechanism of an Al–Cu–Mg alloy. An AA2524 alloy was pre-aged at 180 °C to obtain S′/S precipitates with various sizes. The results showed that the precipitate size increased approximately linearly to ≈32 nm, ≈60 nm, and ≈105 nm after 3 h, 6 h, and 12 h of pre-aging, respectively. The growth of precipitate could significantly shorten the primary creep stage, despite the fact that the steady-state creep behavior was similar to that of the as-received alloy, as revealed by the macro tensile creep tests at 180 °C and 180 MPa. This led to a stress exponent (2.4–2.5) of the Al alloy with various precipitate sizes that was quite close to that of the as-received Al alloy, implying a steady-state creep mechanism dominated by grain boundary sliding and dislocation interactions. Finally, the micro-creep tests showed a minor role of the precipitate size on the steady-state creep mechanism, as evidenced by the similar strain rate sensitivity (0.0169–0.0186), activation volume (≈27 b3), and the results of a detailed transmission electron microscopy analysis of all tested alloys.

Analysis of Steady State Creep Behaviour in Spherical Vessels Made of Composite Material

2019 ◽  
Vol 18 ◽  
pp. 3401-3408 ◽  
Author(s):  
Sukhjinder Singh Sandhu ◽  
Tejeet Singh ◽  
V.K. Gupta
Keyword(s):  
Composite Material ◽  
Steady State ◽  
Creep Behaviour ◽  
Steady State Creep

A Modified Peric Model for Al-Mg Alloy Sheet with Rate-Independent Initial Yield Stress at Warm Temperatures

2019 ◽  
Vol 287 ◽  
pp. 3-7
Author(s):  
Yong Zhang ◽  
Qing Zhang ◽  
Yuan Tao Sun ◽  
Xian Rong Qin
Keyword(s):  
Flow Stress ◽  
Plastic Strain ◽  
Strain Rate ◽  
Yield Stress ◽  
Constitutive Models ◽  
Mg Alloy ◽  
Initial Yield Stress ◽  
Initial Yield ◽  
Rate Dependent ◽  
Dependent Flow

The constitutive modeling of aluminum alloy under warm forming conditions generally considers the influence of temperature and strain rate. It has been shown by published flow stress curves of Al-Mg alloy that there is nearly no effect of strain rate on initial yield stress at various temperatures. However, most constitutive models ignored this phenomenon and may lead to inaccurate description. In order to capture the rate-independent initial yield stress, Peric model is modified via introducing plastic strain to multiply the strain rate, for eliminating the effect of strain rate when the plastic strain is zero. Other constitutive models including the Wagoner, modified Hockett–Sherby and Peric are also considered and compared. The results show that the modified Peric model could not only describe the temperature-and rate-dependent flow stress, but also capture the rate-independent initial yield stress, while the Wagoner, modified Hockett–Sherby and Peric model can only describe the temperature-and rate-dependent flow stress. Moreover, the modified Peric model could obtain proper static yield stress more naturally, and this property may have potential applications in rate-dependent simulations.

Sign in / Sign up

Export Citation Format

Share Document