Difference Between Hardness and Toughness

While thinking about the strength of a material, Hardness & Toughness are the properties that come into consideration. You may think that both of these properties are the same. But that’s not true. Both of them are different. In fact, a material that has more hardness generally has less toughness and the material which has more toughness generally has less hardness. But there may also be some exceptions.

Now let’s get into a brief introduction of both of these properties of the material, before talking about the difference between them…

Hardness is the property or ability of a material by virtue of which it can resist abrasion, wear, scratching, penetration, etc. The hardest material, known at present, is the diamond. Hardness is tested by various hardness tests like the Rockwell Hardness, Brinell Hardness, Vickers Hardness Test, etc. The Hardness Testing Machine measures the hardness by measuring the indentation.

On the other hand, Toughness is the measure of the amount of the load or force that a material can absorb before fracture. You can also say that it is actually the maximum amount of energy that a material can absorb before fracturing. Various Toughness Tests are Impact Toughness, Fracture Toughness, Notch Toughness tests, etc.

Difference Between Hardness and Toughness or Hardness vs Toughness

Some of the most important points highlighting the difference between Hardness and Toughness are as follows:

1. A material’s ability to resist or withstand abrasion, wear, scratching, penetration, etc is measured as “Hardness”. And, on the other hand, the maximum amount of force or energy that a material is able to absorb before it gets fractured is measured as “Toughness”
2. Hardness can be tested by the Rockwell Hardness, Vickers Hardness, Brinell Hardness Test, etc. On the other hand, Toughness can be tested by Notch Toughness, Fracture Toughness, Impact Toughness tests, etc.
3. Hard Materials cannot be easily scratched and Tough Materials cannot be easily broken.
4. The hardest material is Diamond. On the other hand, tough materials are Mild Steel, Magnesium, etc.

So these are the most important points highlighting the difference between Toughness and Hardness. Do you think there is any other important difference that I have missed to mention above? If you think so, please give your response in the comments below. And, if you have any confusion or query in your mind about the topic discussed above, you can ask your question also, using our comment section below. I will be there to answer everything.

Example of Hard Materials

Hard materials include diamond, quartz, boron carbide, tempered steel, ice, concrete, and granite. The hardness of a material refers to its ability to withstand wear and tear, scratching, and abrasion cutting.

Various Tests Used to Measure Hardness

• The Rockwell hardness test

Rockwell is a rapid hardness test technique that was designed for production control and has a direct printout. Generally speaking, more significant sample geometries are used. A kind of ‘quick test’ that is utilized chiefly for metallic materials.

• The Vickers hardness test

Vickers hardness testing is used to determine the hardness of all solid materials, including metallic materials. To determine the hardness of the indent, the diagonals of the indentation are measured optically and entered into a table or formula.

• The Knoop hardness test

The microhardness testing range, the Knoop (HK) test, is a viable alternative to the Vickers test. In particular, it is utilized to prevent breaking in brittle materials and make the hardness testing of tiny layers of material much more convenient.

Factors Affecting Toughness

•  Alloying elements
•  Manufacturing methods
• Microstructure
• Temper state
• Service application (e.g., temperature, strain rate, strength-to-ductility ratio, and the presence of stress concentrators) are all broad variables that affect Toughness.

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Below there are the links to some other important and useful articles that you should not miss to read:

Difference Between Malleability and Ductility Explained in Detail

Tensile Test of Mild Steel