The Mechanism of Internal Stress Superplasticity

1990 ◽  
Vol 196 ◽  
Author(s):  
B. Derby
Keyword(s):  
Thermal Cycling ◽  
Internal Stress ◽  
Metal Matrix Composites ◽  
Plastic Flow ◽  
Test Data ◽  
Metal Matrix ◽  
Mechanical Test ◽  
Matrix Composites ◽  
External Stresses ◽  
Current Mechanism

ABSTRACTThe phenomenon of internal stress superplasticity is reviewed and the theoretical mechanical foundations of current mechanism models of the process examined. These models are shown to be based on two different principles: i.e. a biased internal plastic flow, or an enhanced creep generated by a superposition of internal and external stresses. Mechanical test data is shown to be more consistent with enhanced plasticity models in zinc and metal matrix composites for deformation during thermal cycling.

Damage of Short-Fiber-Reinforced Metal Matrix Composites Considering Cooling and Thermal Cycling

1999 ◽  
Vol 122 (2) ◽  
pp. 203-208 ◽  
Author(s):  
Chuwei Zhou ◽  
Wei Yang ◽  
Daining Fang
Keyword(s):  
Thermal Cycling ◽  
Metal Matrix Composites ◽  
Stress Drop ◽  
Metal Matrix ◽  
Failure Modes ◽  
Short Fiber ◽  
Uniaxial Tensile ◽  
Matrix Composites ◽  
Fiber Reinforced ◽  
Matrix Damage

Mechanical properties and damage evolution of short-fiber-reinforced metal matrix composites (MMC) are studied under a micromechanics model accounting for the history of cooling and thermal cycling. A cohesive interface is formulated in conjunction with the Gurson-Tvergaard matrix damage model. Attention is focused on the residual stresses and damages by the thermal mismatch. Substantial stress drop in the uniaxial tensile response is found for a computational cell that experienced a cooling process. The stress drop is caused by debonding along the fiber ends. Subsequent thermal cycling lowers the debonding stress and the debonding strain. Micromechanics analysis reveals three failure modes. When the thermal histories are ignored, the cell fails by matrix damage outside the fiber ends. With the incorporation of cooling, the cell fails by fiber end debonding and the subsequent transverse matrix damage. When thermal cycling is also included, the cell fails by jagged debonding around the fiber tops followed by necking instability of matrix ligaments. [S0094-4289(00)01202-0]

S102 Residual Stresses in Metal Matrix Composites for Heat Sink Applications During Thermal Cycling

2008 ◽  
Vol 23 (2) ◽  
pp. 188-188
Author(s):  
M. Schöbel ◽  
H. P. Degischer ◽  
T. Buslaps ◽  
M. di Michiel ◽  
T. Poeste ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Thermal Cycling ◽  
Metal Matrix Composites ◽  
Heat Sink ◽  
Metal Matrix ◽  
Matrix Composites

Mechanical Properties of Stirred SiC Reinforced Aluminium Alloy: Stir Casting with Different Composition of SiC, Blade Angle and Stirring Speed

2012 ◽  
Vol 622-623 ◽  
pp. 1335-1339 ◽  
Author(s):  
Azrol Jailani ◽  
Siti Mariam Tajuddin
Keyword(s):  
Mechanical Properties ◽  
Aluminium Alloy ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Particle Distribution ◽  
Mechanical Test ◽  
Metallographic Analysis ◽  
Matrix Composites ◽  
Blade Angle ◽  
Sic Reinforcement

Discontinuously reinforced cast metal-matrix composites are increasingly attracting the attention of aerospace, automotive and consumer goods industries. In this study, SiC particle reinforced aluminium alloy is selected to produce metal matrix composites (MMC) using different of parameters blade angle and stirring speed and composition of SiC reinforcement. Mechanical test, metallographic analysis and fracture analysis will be conducted to investigate mechanical properties of material and to observe particle distribution of SiC reinforcement and fracture properties respectively with varies angles and stirring speed of impellers and different composition of SiC reinforcement. Metallographic analysis on composition records at low speed, there exist a particle collection and gas existence on the specimen. At blade angles of 300, increasing on stirring speed and composition of SiC reinforcement may result better of particle distribution. For mechanical test, different composition of SiC reinforcement, blade angle and stirring speed will be affecting a mechanical property of material. The result of the experiment showed at blade angle 300, stirring speed 100rpm and 10% composition of SiC reinforcement give better result of hardness, ultimate strength, energy absorption, microstructure and fracture of composite. For this study, it proved that at the lower blade angle and the increment on stirring speed and composition of SiC reinforcement give a better result on particle distribution of SiC reinforcement, fracture and mechanical properties for A1-MMC.

Non-destructive characterisation of microstructure evolution in Mg based metal matrix composites submitted to thermal cycling

1997 ◽  
Vol 234-236 ◽  
pp. 774-777 ◽  
Author(s):  
František Chmelik ◽  
Zuzana Trojanová ◽  
Jens Kiehn ◽  
Pavel Lukáč ◽  
Karl Ulrich Kainer
Keyword(s):  
Thermal Cycling ◽  
Metal Matrix Composites ◽  
Microstructure Evolution ◽  
Metal Matrix ◽  
Matrix Composites ◽  
Non Destructive
Sign in / Sign up

Export Citation Format

Share Document