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27 Cards in this Set
- Front
- Back
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What is elastic deformation? |
It is non permanent deformation when an applied load is released the piece returns to its original shape. |
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Atomically what is the modulus of elasticity? |
It is the measure of the resistance to separation of adjacent atoms or the inter-atomic bonding forces. |
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What is anisotropic? |
Directionality dependence of properties. Elastic behavior that varies with crystallographic direction. |
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What is isotropic? |
Properties that are independent of the direction of measurement. |
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Atomically what is plastic deformation? |
The breaking of bonds with original atoms neighbors and reforming of bonds with new neighbors as large numbers of atoms or molecules move relative to one another. |
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What is ductility? |
The measure of the degree of plastic deformation that has been sustained at fracture. |
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Why is ductility important? |
It indicates the degree a material can plastically deform before fracture. Also it indicates the degree of allowable deformation during fabrication operations. |
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How does temperature affect YS, TS, E, and ductility. |
YS, TS and E decrease with temperature while ductility increases with temperature. |
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What is resilience? |
It is the capacity of a material to absorb energy when it is elastically deformed and then to have this energy recovered during unloaded. |
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What is toughness |
It is a property that indicates a material's resistance to fracture when a crack is present. Also defined as the ability of a material to absorb energy and plastically deform before fracturing. |
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How does the elastic modulus relate to stiffness? |
It is the resistance to elastic deformation the greater the modulus the stiffer the material. |
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What is Brinell Hardness test a function of? |
It is a function of a magnitude of a load as well as the diameter of the resulting indentation. |
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What are sources of inaccuracies for Rockwell Hardness test? |
Inaccuracies can result if the test specimen is too thing. Also if an identation is made to close a specimen edge or if two identations are made too close to one another. |
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What are five factors that lead to scatter in measured material properties. ch.8 |
1) Test method 2) Apparatus calibration 3)Operator bias 4)Variation in fabrication procedure 5)Material inhomogeneities and/or compositional differences |
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Explain the difference between ductile and brittle fraction. ch.8 |
Ductile metals exhibit extensive plastic deformation and high energy absorption before fracture. However, for brittle fracture there is little or no plastic deformation and low energy absorption. |
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What are some distinctive patters of brittle fracture? ch.8 |
V-shaped "chevron" markings may form near the center of the fracture cross section that point back toward the crack initiation site. Also lines or ridges that radiate from the origin of the crack in a fanlike pattern. C.C.S. |
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What is transgranular? ch.8 |
It means the fracture cracks pass through the grains. |
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What is intergranular? |
It is crack propagation along the grain boundaries. |
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What are stress raisers? ch.8 |
They are flaws that amplify an applied stress in their locale. |
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PUT EXAMPLE 8.1 IN C.C.S. |
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What is fracture toughness? ch.8 |
A measure of a material's resistance to brittle fracture when a crack is present/ |
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What is plain strain? ch.8 |
When a load operates on a crack in the manner |
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What is one of the primary functions of the Charpy and Izod tests? ch.8 |
To determine whether a material experiences a ductile-to-brittle transition with decreasing temperature and if so the range of temperature over which it occurs. |
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What kind of crystal structure has ductile-to-brittle transition? ch.8 |
The ductile-to-brittle transition is represented by the middle curve of Figure 8.15. As noted,this behavior is typically found in low-strength steels that have the BCC crystal structure. |
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How does grain size affect toughness? ch.8 |
Refining the grain size both strengthens(Section 7.8) and toughens steels. In contrast, increasing the carbon content, although itincreases the strength of steels, also raises their CVN transition, as indicated in Figure 8.16. |
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What is fatigue? ch.8 |
Fatigue is a form of failure that occurs in structures subjected to dynamic and fluctuating stresses. |
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What is fatigue limit? ch.8 |
It is a limiting stress level below which fatigue failure will not occur. The fatigue limit represents the largest value of fluctuating stress that will not cause failure for essentially en infinite number of cycles. |
