Calculating Alloy Strength with Dispersed Particles: Expert Help Needed

[maha1986]

Major stuck on a question for my assignment, totally wracked my brain and my mates too! here is the qtn

An alloy has an initial shear yield strength. After ageing to an overaged condition the matrix now contains particles where the average centre to centre spacing is 275nm. The average particle diameter is 75nm. Determine the new strength of the alloy taking into account the strengthing contribution from the disperesd particles.

Data

Burgers vector the dislocation= 0.286nm
shear modulas of the alloy 80GPa

We have worked out the addiitional strenght but can't seem to work out the initial to add it to the additional to work out the new!

Please please, anybody... help me

 

[Mapes]

If you don't know the alloy, you're not going to be able to estimate its initial yield strength (in the lack of any strengthening particles) with any precision. As you probably know, the yield strength of alloys depends on many things, including the component metals, the grain size, and the dislocation density.

 

[piercas]

Hello,

I understand that you are stuck on a question for your assignment regarding the calculation of alloy strength with dispersed particles. This can be a challenging topic, but I am here to help.

Firstly, let's review the information provided in the question. We have an alloy with an initial shear yield strength, which has been aged to an overaged condition. This means that the matrix now contains particles with an average spacing of 275nm and an average diameter of 75nm. We also have the following data: the Burgers vector of the dislocation is 0.286nm and the shear modulus of the alloy is 80GPa.

To determine the new strength of the alloy, we need to take into account the contribution from the dispersed particles. This contribution is known as the Orowan strengthening mechanism. It is caused by the interaction between the dislocations and the particles, which creates an additional force that resists the movement of dislocations.

In order to calculate the new strength of the alloy, we need to first determine the additional strength provided by the dispersed particles. This can be calculated using the following formula:

σ_O = Gb/λ

Where:
σ_O = additional strength
G = shear modulus of the alloy
b = Burgers vector
λ = average spacing between particles

Substituting the values given in the question, we get:

σ_O = (80GPa)(0.286nm)/(275nm) = 0.083 GPa

Now, to determine the new strength of the alloy, we need to add the additional strength to the initial strength. However, the initial strength is not given in the question. It is possible that it was given in a previous part of the question or it needs to be calculated using other information. I suggest reviewing the previous parts of the question or checking if there is any other information provided that can help you calculate the initial strength.

I hope this helps. If you have any further questions or need clarification, please don't hesitate to ask. Good luck with your assignment!