In physics, it is common to find the two worlds yield strength and tensile strength together. Both being the measure of the strength of a material, these two terms have some differences. The difference lies in the fact that yield strength is the minimum force put on the material to cause it to change shape. But the tensile strength is the maximum force it bears before totally shattering.
Yield Strength vs Tensile Strength
The main difference between yield strength and tensile strength is that yield strength is the smallest amount of force that can start the beginning of the deformation of an object. However, tensile strength is just the opposite of that, being the maximum force to cause breakage in an object.
Yield strength has practical use while designing, which is a measure of strength. Yield strength is the minimum stress, which is applied to an object before it changes its shape in such a way that you can not reverse it. Another term associated with it is stress, which means the intermolecular force. Increasing in stress on a material, it slowly changes its shape to such a way that it’s irreversible.
In general terms, it means the maximum stress that is given on material before it breaks down. When material stress increases, the intermolecular forces between the material will be lower than the external forces that deform the material. Due to the stress of deformation being higher, the material is incapable of resisting and breaks.
Comparison Table Between Yield Strength and Tensile Strength
| Parameters of Comparison | Yield Strength | Tensile Strength |
| Condition of material | This tells the irreversible deformation of the material | This tells about the breakage of the material |
| Stress | It is the minimum stress that causes deformation | It is the maximum strength to cause total breakage |
| Position in graph | It comes before the point of ultimate strength | It comes after the point of ultimate strength |
| Intermolecular forces | The intermolecular forces are just higher than the outside deformation forces | The intermolecular forces break from each other, thereby breaking the material. |
| Numerical value | The numerical value of yield strength is less than tensile strength. | The numerical value of tensile strength is more than yield strength. |
What is Yield Strength?
Yield strength can be said to be the measure of the strength of an object. Stress means the amount or magnitude of the force you need to apply to something to cause deformation. That is directly linked to yield strength. It is the least (minimum) amount of stress you put upon a material to cause it to deform beyond repair. The deformation has to be irreversible.
The basic difference that the yield strength has from the tensile strength. In the case of yield strength, the stress that’s applied is minimum. Yield strength also has another in physics that is Elastic Limit. Elastic limit or yield strength is that point of the stress strength graph beyond which if stress is continued to be applied, the object will be irreversibly deformed beyond repair.
Before reaching the yield strength, any damage or deformation reached can be reversed and they are called elastic deformation. After the point of elastic limit is reached, it damages beyond repair and is called plastic deformation.
Its SI unit is Newton per (meter) ² which is also called Pascal. Yield strength is used in several areas of engineering mainly to know the maximum load that can be applied to the part of a machine before it starts to get deformed.
What is Tensile Strength?
Tensile strength has its practical applications in the field of engineering. The tensile strength is the maximum amount of stress that an object can bear before it gets broken. Tensile strength is an intensive property. An intensive property does not depend upon the size of the object used. The limit of tensile strength comes after the elastic limit or yield after it attains, the material breaks.
The difference between yield strength, and tensile strength depends on few parameters.Yield strength is the minimum amount of stress applied to an object to cause a deformation beyond repair. On the other hand, tensile strength is the amount of stress that the object can bear or withstand before it starts to break.
In this case, the externally applied force on the object is much greater than the intermolecular forces of attraction that bind the object together. There are mainly three types of tensile strength which are yield strength along with ultimate strength, and at last, the breaking strength.
Many tests are there for measuring the tensile strength of an object. This test has applications in the construction industry, vehicle designing, rockets designing, safety and fitness industry, packing, textile industry, etc. As it measures the strength, its unit is also Newton per (meter) ² or Pascal. We can find it by dividing force with the area concerned ( F/A)
Main Differences Between Yield Strength and Tensile Strength
- Yield strength talks about the irreversible deformation taking place in a material. Whereas tensile strength talks about the breakage of the material
- In the case of yield strength, it is the minimum amount of stress that the object can handle before it starts to get deformed. Whereas tensile strength is the maximum amount of stress that can be applied before the material starts to fall apart.
- Yield strength comes before the tensile strength in the graph. Whereas tensile strength comes before yield strength in the graphs.
- In yield strength, the intermolecular force still exists but is weaker than the breakage point. In tensile strength, intermolecular forces break.
- Yield strength has a higher numerical value than tensile strength whereas tensile strength has a higher numerical value.
Conclusion
Yield strength and tensile strength have frequent use in real-life applications. Both, as we can see, are the measurements of strength. Yield strength only differs from the fact. It is the lowest amount of stress that a material can stand before it gets deformed beyond repair. But tensile strength is the maximum or highest amount of stress that causes the material to fall apart.
Both these have the same Si units and are intensive properties. Intensive which means, they do not depend upon the size of the material. Yield strength comes under tensile strength.
It is crucial In the field of engineering and designing while creating various vehicles, air crafts. And check the strength of metals that are used in construction, making armors is when we use these. And simply by dividing force with the area, these can be found. Both these terms have utmost importance, and you should know about them.
References
- https://link.springer.com/article/10.1007/s11665-008-9225-5
- https://www.sciencedirect.com/science/article/pii/S0921509317309188