Brittle vs. Ductile Materials?

Question

Is there a way to determine whether a material can be considered brittle or ductile based on its yield strength or ultimate strength in compression & tension?

Answer 1

The following website provides good information as to the actual definition of ductile and brittle.
http://en.wikipedia.org/wiki/Tensile_strength

The Tensile Strength or even the Yield Strength are not good descriptors of the ductility or brittleness of a material.

You would be better off using the % elongation (1) or even the modulus of elasticity (2).

(1) http://www.engineersedge.com/material_science/ductility.htm

(2) http://en.wikipedia.org/wiki/Elastic_modulus

The percent elongation might be a better gauge to use and it is generally easy to come by.

Hope that helps!

Answer 2

Ductile Vs Brittle

Answer 3

This Site Might Help You.

RE:
Brittle vs. Ductile Materials?
Is there a way to determine whether a material can be considered brittle or ductile based on its yield strength or ultimate strength in compression & tension?

Answer 4

Heres what it says in my Mech D textbook

Ductile materials are normally classified such that Ef>=.05 and have an identifiable yield strength that is often the same in compression as in tension (Syt = Syc =Sy). Brittle materials , Ef<.05 do not exhibit an identifiable yield strength, and are typically classified by ULTIMATE tensile and compressive strengths, Sut and Suc, respectively (Where Suc is given as a positive quantity)

basically a brittle material wont be classified by a yield strength because they don't yield they just snap or break.

Answer 5

The characteristics of ductile and brittle materials are different when it breaks, when you apply the tension, the stress-strain curve of both the materials will be different, thats one way to know.

Other way to find out it is when you break it under transverse load, the ductile material will break but not break apart in two pieces, it will be connected by one end. The brittle material will be broken apart in two pieces

Answer 6

Ductile and brittle materials can be identified by running a series of charpy impact tests on them.
The ductile materials will absorb more energy before fracturing than the brittle materials.

See this article: http://www.key-to-steel.com/Articles/Art136.htm

Answer 7

A physical change is something that can happen to a molecule without changing its identity. A chemical change is something that happens that changes the identity of the molecule. Physical properties are properties that you can observe without anything changing its identity. Chemical properties are ones that you have to change its identity in order to observe. Physical changes do not make new substances. Chemical changes do. Shape is a physical property. You can change shape without changing molecular identity (even though salt is not a molecule, it is an ionic compound. You'll get to that later). Dew forms when water changes from a gas to a liquid. It's still water, though, so the change is physical, not chemical. Only metals are malleable and ductile (that means you can bend and twist and squish them without breaking them. Silly putty is actually a complex suspended compound, it's not made of "silly putty molecules"). It has to do with something called metallic bonding, but you probably won't get to that for some time, maybe not even in that class. In a reaction, you start with reactants and end with products, not the other way around. density = mass/volume. You need to measure both before getting density.

Answer 8

yeah by breaking it