What causes some materials to have upper and lower yield points?

Thread starter ||spoon||
Start date May 5, 2010
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Materials Points Yield

In summary, the yield point of a material is the stress level at which it begins to permanently deform. The presence of upper and lower yield points is caused by the internal structure of the material and is determined through stress-strain curve testing. The magnitude of these points is influenced by factors such as material type, composition, and temperature. Understanding yield points is important in material science for determining strength and selecting appropriate materials for different applications.

May 5, 2010

||spoon||

Hey,

Just wondering how to explain the yield point run-off for low carbon steel. Why does LCS have an upper yield point, followed directly by a lower yield point?

Thanks,

-Spoon

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May 5, 2010

Mapes

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Answered recently https://www.physicsforums.com/showpost.php?p=2605350&postcount=8".

Last edited by a moderator: Apr 25, 2017

May 5, 2010

||spoon||

Thats what i thought ;)

Thanks

1. What is the definition of yield point?

The yield point of a material is the stress level at which it begins to permanently deform or change shape, even after the applied stress is removed.

2. What causes materials to have upper and lower yield points?

The presence of upper and lower yield points is caused by the internal structure of the material and how it responds to external forces. This is due to the interactions between the atoms and molecules within the material.

3. How are upper and lower yield points determined?

Upper and lower yield points are determined through stress-strain curve testing, where the material is subjected to increasing levels of stress until it reaches its yield point. The corresponding strain at which the yield point occurs is then measured and recorded.

4. What factors influence the magnitude of the upper and lower yield points?

The magnitude of the upper and lower yield points is influenced by factors such as the type of material, its composition and structure, temperature, and the rate at which stress is applied.

5. Why is understanding yield points important in material science?

Understanding yield points is crucial in material science as it helps engineers and scientists determine the strength and durability of a material. It also allows for the selection of appropriate materials for different applications, ensuring the safety and reliability of structures and products.