scholarly journals Crystal-Plasticity-Finite-Element Modeling of the Quasi-Static and Dynamic Response of a Directionally Solidified Nickel-Base Superalloy

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 2990
Author(s):  
Rafael Sancho ◽  
Javier Segurado ◽  
Borja Erice ◽  
María-Jesús Pérez-Martín ◽  
Francisco Gálvez
Keyword(s):  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Crystal Plasticity ◽  
Dynamic Testing ◽  
Rate Sensitivity ◽  
Growth Direction ◽  
Nickel Base Superalloy ◽  
Directionally Solidified ◽  
Nickel Base ◽  
Base Superalloy

The flow stress behaviour of a directionally solidified nickel-base superalloy, MAR-M247, is presented through the combination of experiments and crystal-plasticity simulations. The experimental campaign encompassed quasi-static and dynamic testing in the parallel and perpendicular orientation with respect to the columnar grains. The material showed low strain-rate sensitivity in all cases. Virtual samples were generated with DREAM3d and each grain orientation was established according to the DS nature of the alloy. The elasto-visco-plastic response of each crystal is given by phenomenological-base equations, considering the dislocation–dislocation interactions among different slip systems. The hardening-function constants and the strain-rate sensitivity parameter were fitted with the information from tests parallel to the grain-growth direction and the model was able to predict with accuracy the experimental response in the perpendicular direction, confirming the suitability of the model to be used as a tool for virtual testing. Simulations also revealed that in oligocrystalline structures of this type, the yield-strength value is controlled by the grains with higher Schmid factor, while this influence decreases when plastic strain increases. Moreover, the analysis of the micro-fields confirmed that grains perpendicular to the loading axis are prone to nucleate cavities since the stresses in these regions can be twice the external applied stress.

scholarly journals Deformation Texture Evolution in Flat Profile AlMgSi Extrusions: Experiments, FEM, and Crystal Plasticity Modeling

2021 ◽  
Vol 8 ◽  
Author(s):  
Tomas Manik ◽  
Knut Marthinsen ◽  
Kai Zhang ◽  
Arash Imani Aria ◽  
Bjørn Holmedal
Keyword(s):  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Crystal Plasticity ◽  
Texture Evolution ◽  
Rate Sensitivity ◽  
Deformation Texture ◽  
Fiber Texture ◽  
Electron Back Scatter Diffraction ◽  
Slip Systems ◽  
Flat Profile

In the present work, the deformation textures during flat profile extrusion from round billets of an AA6063 and an AA6082 aluminium alloy have been numerically modeled by coupling FEM flow simulations and crystal plasticity simulations and compared to experimentally measured textures obtained by electron back-scatter diffraction (EBSD). The AA6063 alloy was extruded at a relatively low temperature (350°C), while the AA6082 alloy, containing dispersoids that prevent recrystallization, was extruded at a higher temperature (500°C). Both alloys were water quenched at the exit of the die, to maintain the deformation texture after extrusion. In the center of the profiles, both alloys exhibit a conventional β-fiber texture and the Cube component, which was significantly stronger at the highest extrusion temperature. The classical full-constraint (FC)-Taylor and the Alamel grain cluster model were employed for the texture predictions. Both models were implemented using the regularized single crystal yield surface. This approach enables activation of any number and type of slip systems, as well as accounting for strain rate sensitivity, which are important at 350°C and 500°C. The strength of the nonoctahedral slips and the strain-rate sensitivity were varied by a global optimization algorithm. At 350°C, a good fit could be obtained both with the FC Taylor and the Alamel model, although the Alamel model clearly performs the best. However, even with rate sensitivity and nonoctahedral slip systems invoked, none of the models are capable of predicting the strong Cube component observed experimentally at 500°C.

An Experimental Study on Elevated Temperature Biaxial Bulge Test

2012 ◽  
Vol 430-432 ◽  
pp. 539-542 ◽  
Author(s):  
Ho Sung Lee ◽  
Jong Hoon Yoon ◽  
Joon Tae Yoo
Keyword(s):  
Elevated Temperature ◽  
Strain Rate ◽  
Rate Sensitivity ◽  
Metal Sheet ◽  
Bulge Test ◽  
Nickel Base Superalloy ◽  
Test Results ◽  
Forming Process ◽  
Uniaxial Test ◽  
Nickel Base

By using biaxial bulge test, it is possible to predict sheet metal forming behavior during hot forming process. The purpose of this study is to obtain materials parameters for elevated temperature forming condition during biaxial bulge test of a nickel base superalloy in hemispherical die. At constant gas pressure, the strain rate in which the metal sheet experiences varies and therefore the strain rate sensitivity can be obtained in a single loading. Biaxial bulge tests on superalloy metal sheet were performed and results are in satisfactory agreement with uniaxial test results at elevated temperature.

Microstructural evolution of a directionally solidified nickel-base superalloy during thermal fatigue

Rare Metals ◽  
2011 ◽  
Vol 30 (S1) ◽  
pp. 477-481 ◽  
Author(s):  
Pengcheng Xia ◽  
Lei Yang ◽  
Jinjiang Yu ◽  
Xiaofeng Sun ◽  
Hengrong Guan ◽  
...  
Keyword(s):  
Microstructural Evolution ◽  
Thermal Fatigue ◽  
Nickel Base Superalloy ◽  
Directionally Solidified ◽  
Nickel Base ◽  
Base Superalloy
Sign in / Sign up

Export Citation Format

Share Document