47 Questions 18 Answers 0 Followers
Questions related from Rajorshi Koyal
Question: Calculate the equilibrium value of vacancies concentration for copper per atom of the order of 10^4 at 1000K the energy for vacancy formation is 0.9eV/atom. Answer:N=N_0+exp(−Q/RT)is...
08 August 2019 6,009 5 View
There are two equations that are primarily used in context of the facture stress one with sqrt(2 *gamma*E/a0) and the other with sqrt(2*gamma*E/pi*C).I do not understand which one to use while...
08 August 2019 2,650 4 View
What is the significance of h^2+k^2+l^2 values in BCC and FCC?I have seen how h,k,l values are the ones which are relatable to the structure factor theorem and why all odd or all even and sum...
07 July 2019 4,692 4 View
We seem the apply the lever rule even when we calculate the microstructure at room temperature.However whenever we draw the phase diagram we seem to draw them for a huge range of temperature and...
07 July 2019 3,340 12 View
Whenever there is a concept of diffusion involved and we need to decipher what is going to happen we tend to draw common tangent s in the phase field diagrams and decide which direction the...
07 July 2019 9,694 1 View
X-ray diffraction pattern is obtained from FCC polycrystalline aluminium (lattice parameter = 0.405 nm) using Cr-K📷 radiation of wavelength 0.2 nm. The maximum number of peaks that can be observed...
07 July 2019 3,719 3 View
Please answer this in detail as much as possible.
07 July 2019 7,543 1 View
Stacking Faults and its association with partial dislocations seem to bother me day in and day out.With regard to this I do not understand how Partial dislocations lead to stacking faults and not...
07 July 2019 7,447 1 View
With regard to this particular phenomenon that occurs there are a couple of things that need to be addressed.Firstly,Why do I have a region of stacking fault in that particular junction. I mean...
07 July 2019 3,375 12 View
Particularly with regard to problems in diffusion I find that the factor Dt is generally taken constant to solve certain lengthy and difficult looking problems.If possibly can anyone give me an...
07 July 2019 2,179 7 View
The property of whether a substance is paramagnetic or antiferromagnetic is something that is bothering me.I know that for sure what the things are in terms of magnetic domains and stuff.However...
07 July 2019 2,236 1 View
Why does carbon atoms occupy the octahedral void in BCC atoms even though they are smaller than the tetrahedral voids? If the reason is because of less distortion I would be very pleased to see...
07 July 2019 1,197 1 View
It seems that we have a perennial notion of relation Austentite and Ferrite in Fe-C phase diagram however we refer to them as gamma or alpha iron.Is having a minimal carbon content necessary for...
07 July 2019 1,406 8 View
I do not understand why the shell equation is being applied and most importantly there is nothing spherical here so why should the shell equation even be pondered about?Please refer to the...
07 July 2019 3,621 4 View
In the given question is it not that the terms containing partial differential of pressure and temperature have switched the associations? Like dp should be in place of dT and dt should be in...
07 July 2019 7,568 5 View
Generally as much as we have studied phase separation mainly deals with two components separating into separate phases.However I do not understand why there would be something that will act...
07 July 2019 6,699 2 View
The given below figure is the Gibbs free energy versus pressure plot for three phases, solid (S ), liquid (L ), and gas (G ), near the triple point for the one component system. It is known that...
06 June 2019 9,055 3 View
Please explain Frank read source with close reference to the formula τ =Gb/l.Somewhere I have heard that l is the length of the Frank Read source please explain me this vividly.
06 June 2019 796 3 View
I have tried solving this issue by using the relation τ =Gb/l.However, in this context I do not understand how to get the value for b because it is a well given relation where I can substitute τ...
06 June 2019 8,809 6 View
I know that P2O5 production is favoured by increasing O content but why are we using high activity of FeO to favour dephosphorization?Please explain in detail keeping in mind that I am reading...
06 June 2019 9,997 10 View
There are a lot of things to be known from a G vs X curve starting from the y intercepts to drawing common tangents for finding equilibrium conditions(for chemical potential).what has the y...
06 June 2019 3,321 0 View
Please explain me as simply as possible as if I am reading for the first time.
05 May 2019 6,456 2 View
Proove that the dislocation reaction is vectorially correct a/2[10-1]-->a/6[21-1]+a/6[11-2]...Please solve this and tell me the approach.
05 May 2019 8,854 3 View
It's seems that addition of carbon atoms increase the hardness by solid solution strengthening. However I do not know why it will have more effect on ferrite than on Austenite.
03 March 2019 8,042 4 View
Please explain precisely why the yield point apprears prematurely on unloading the sample.
02 February 2019 3,879 1 View
Why are dislocations unstable thermodynamically contrary to that of point defects?
12 December 2018 6,470 6 View
Please explain me the process of microsegregation in case of nucleus with close reference to the diffusion mechanism that are involved at solute and solid liquid interface.
12 December 2018 6,319 11 View
I have drawn the cubic system and have marked the tetrahedral and octahedral voids myself(see attachment).However I do not understand why all of them will be having index (1/4,1/4,1/4).Someone...
11 November 2018 3,301 1 View
In this particualr question: "Assume that in order to determine the heat of formation of Carbon dioxide the folowing data was obtained: (i)Upon thee combustion of 0.6g of graphite to CO2 with...
10 October 2018 4,019 1 View
I do not understand why the two volumes are added instead of subtraction .The picture is attached herewith.(Refer to the place where H=U+PV and delta V is sum of all components).That is the place...
10 October 2018 7,838 5 View
For Miller Indices of planes if we encounter a case where the plane passes through the origin then I have heard that the only remedy can be arrived by shifting the origin to a different...
10 October 2018 2,523 2 View
Degree of freedom is something which comes instinctively while studying phase diagrams and all.I would be happy if someone could give me the statistical interpretation right from justifying why...
09 September 2018 4,560 0 View
The temperature can vary from freezing ones in poles to those in Sahara. So why is it taken at 298K?Why is the pressure taken to be a certain numerical value when even it can vary?
09 September 2018 2,400 1 View
a)Adiabatic flame temperature b)the po2 (partial pressure of O2)in the resulting combustion gas.
09 September 2018 7,802 1 View
Can anyone share the solutions of Dieter,Meyers and Chawla and Hosford(Mechanical Behviour book)?
08 August 2018 5,659 0 View
I would like to know why point defect will not influence density .Please answer me with close reference to a proper diagram.My intuition is because of a localized affair but would be happy if...
08 August 2018 2,915 3 View
It seems I am not so familiar with definite integral being changed to differentials.Can anyone justify me how the T1,P1 values and the limits are being changed to simply T and P as given in the...
08 August 2018 3,039 3 View
Glass and amorphous solids are both non crystalline.However we associate glass with some sort of "supercooled liquid" while it is ofter projected that true crystalline substances are solids.Please...
07 July 2018 4,165 7 View
Explain how a crystalline substance is different from amorphous or else.How to classify substances as a thumb rule into the two categories.
07 July 2018 3,401 1 View
Please explain why offset is taken and elaborate on the same.
07 July 2018 9,002 4 View
I know that only highest density planes help in showing peaks in the diffraction. Firstly I am not convinced why it diffracts and secondly with close reference to my question please explain me...
07 July 2018 7,877 3 View
For a cubic structure (namely FCC, BCC, or simple cubic) we can always draw a plane and predict the plane which has highest density of atoms. Is there any rule of thumb to arrive at such a plane?...
06 June 2018 9,999 5 View
We know that hardening and brittleness go hand in hand in most of the cases.Please explain me what it means physically while it often confuses us when we realize that it is brittle.Please answer...
06 June 2018 6,611 11 View
It is known that at point of instability a triaxial state of stress exists.However I do not understand how we arrive at the relation where the strain hardening exponent is equal to the ultimate...
06 June 2018 2,116 1 View
I have seen that dV=0 is valid as long as necking doesn't start. How does volume change during necking?Does it lose matter?
06 June 2018 1,129 10 View
As per Wikipedia," Flow stress is defined as the instantaneous value of stress required to continue plastically deforming the material - to keep the metal flowing. It is the middle value between...
06 June 2018 1,955 2 View
There is no doubt about the fact that true stain is logarithmic and engineering strain is linear.However it appears to be almost same for small deformation owing to small values in Taylor...
06 June 2018 908 6 View
