Term
| Mechanical properties of metals |
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Definition
Stress versus strain
Hardness
Creep |
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Term
| Mechanical properties of metal is also applicable to ceramics |
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Definition
| Ceramic (brittle fracture, creep) |
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Term
| Tensile test is the answer |
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Definition
A load-versus-elongation curve
Stress-versus-stain curve |
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Term
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Definition
Initial linear portion
Can fully recover to the initial length |
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Term
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Definition
Permanent deformation
Cannot recover to the initial length
Nonlinear portion after the elastic limit |
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Term
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Definition
intersection of the deformation curve with a strain-line parallel to the elastic portion and offset 0.2 % on the strain axis
Stress necessary to generate 0.2% of permanent deformation
Resistance of the metal to permanent deformation |
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Term
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Definition
Yield strength for a low-carbon steel
Upper yield point: distinct break point from the elastic region
Ripple pattern : nonhomogeneous deformation at a point of stress concentration
Lower yield point: at the end of the ripple pattern, start of general plastic deformation |
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Term
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Definition
The linearity of the stress-strain plot in the elastic region
Represents the stiffness of the material |
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Term
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Definition
| The maximum stress after the yield strength |
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Term
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Definition
stress remaining within a structural material after all applied loads are removed
Thermomechanical treatments (welding, machining) |
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Term
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Definition
| The phenomenon of increasing strength with increasing deformation |
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Term
| Cold working (below one-half of the melting point) |
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Definition
| Metal shaping with the advantage of the strain hardening |
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Term
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Definition
1.Engineering stress-strain: stress decreases after the tensile stress
(Area fixed)
2.Actual stress-strain: stress increases after the tensile stress
(necking-Area reduces) |
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Term
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Definition
1.Failure stress varies due to complexity of the final neck down – hard to predict
2.Ductility is the percent elongation at failure
3.Formability(ductility) indicates the general ability of the metal to be plastically deformed
4.Toughness :
Strength + Ductility |
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Term
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Definition
Ceramics and glasses do not demonstrate a significant amount of plastic deformation
Brittle fracture : characteristic of ceramics and glasses
Tension: relatively weak (280 Mpa)
Compression: relative strong (2100 Mpa) |
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Term
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Definition
stretching of atomic bonds in the vicinity of the equilibrium point
Nearly straight-line of F versus a implies linear elastic behavior |
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Term
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Definition
| distortion and reformation of atomic bonds |
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Term
| Difference between theory and practice |
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Definition
Theory (by atomic bonding force): 1000 Mpa (copper)
Practice (shear test): 100 Mpa (copper) |
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Term
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Definition
| becomes more difficult as the individual atomic step distances are increased |
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Term
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Definition
| along high atomic density plane and high-atomic density directions is much easier |
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Term
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Definition
| combination of families of crystallographic planes and directions corresponding to dislocation motion |
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