Transcript Slide 1

MATERIAL RESPONSE TO MICROSTRUCTURAL-,
MECHANICAL- AND THERMAL- STIMULI
Stream: Mechanical Engineering
Dr. Kantesh Balani
(Materials Science & Engineering, IIT Kanpur)
Objective : “To elicit material’s response to microstructural-, mechanical-, and thermal- stimuli.”
Experiments Originally Proposed:
- Been revised for appealing to UG students
- More component of fundamentals included
- Pictorial graphs and bullets of conclusions are added for
clarity
Status: Demo of 6 expt. over the internet in virtual mode.
Under Progress:
1. Fluorescence Microscopy/ Wetting Phenomena
2. Views / reports on any user trials / field tests carried out.
Meetings:
To meet DNC on Mar. 18/19 IIT Kharagpur at Kolkata
Website
http://home.iitk.ac.in/~kbalani/vl-kb/Home%20page.html
Apr. 18, 2011
Objectives
To elicit material’s response to stimuli of:
Creep
Nanoindentation
Flourescence Microscopy
Wetting
Ionic Conductivity
 Thermal + Load
 Mechanical Response
 Biological Surface Response
 Surface Response
 Conductivity
Dr. Kantesh Balani Virtual Lab on Material Response
Apr. 18 2011
Introduction/Aim
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Most materials are seen to behave very similarly w.r.t
time dependent deformation. These general features are
common to many materials with varied crystal structures,
strengthening mechanisms, and strength levels.
Our aim is to develop virtual lab experiemtns for how
materials respond in general with respect to stimulus of:
Creep (Thermal + Load)
 Mechanical (Loading)
 Biological (To Cells)
 Wetting (Surface Response)
 Conductivity (Ionic at Various Temperatures)
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Dr. Kantesh Balani Virtual Lab on Material Response
Apr. 18 2011
Creep and Its Features
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Stage I
Dislocation Climb
away from
obstacles
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Stage II
Rate of
Dislocation climb
equals that of
blocking by
obstacles
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Stage III
Necking occurs,
stress increases
http://home.iitk.ac.in/~kbalani/vl-kb/creep1.html
Dr. Kantesh Balani Virtual Lab on Material Response
Apr. 18 2011
Utilizing Mechanism of Load Transfer
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There will be a spectrum of obstacle‘ strengths’
that resist local deformation.
The model is based on the idea of simply(if
approximately) linking many independent and
simply described elements into a macroscopic
‘whole’.
The model developed here stems from the theory
of thermally activated plastic deformation.
It naturally produces the types of transients
observed on the immediate loading of materials
(primary creep)
In the model’s present form, strain hardening and
recovery processes are not considered.
Dr. Kantesh Balani Virtual Lab on Material Response
Apr. 18 2011
Nanoindentation
Nanoindentation to investigate
mechanical properties:
(i) Hardness
(ii) Elastic modulus
(iii) Plasticity index
Hardness is proportional to the
applied load P divided by the
area of contact surface
Elastic deformation occurs due to
the stretching of the bonds
and comes back to the
original shape upon removal
of loading
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http://home.iitk.ac.in/~kbalani/vl-kb/nano.html
Experiments Completed
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CREEP:
Experiment 1 : Creep Transient Based on Material
Selection (Pt/Mg)
 Experiment 2 : Selection of Obstacle Distance (λ, grain
boundary or precicipitate)
 Experiment 3 : Selection of Obstacle Density (ρ,number
of grains/precipitates)
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NANOINDENTATION:
Experiment 4 : Hardness & Modulus
 Experiment 5: Indent Depth
 Experiment 6: Plastic Work
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http://home.iitk.ac.in/~kbalani/vl-kb/Home%20page.html
Dr. Kantesh Balani Virtual Lab on Material Response
Apr. 18 2011
User Reports
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Will showcase this website on Apr. 19th to students
of CSJM University (Kanpur).
Feedbacks:
 Creep
Experiment is fine
 Polymer Characterization can be added (mainly FTIR)
 Nanoindentation
of polymeric composite
 Will show surface energy by contact angle measurement
 Biological property of polymeric materials will be elicited
(Fluorescence microscopy)
To Be Accomplished
Stage II:
 Completing rest set of experiments
 Fluorescence
microscopy for biological response of
material (Two Experiments)
 Wetting of material by varying its composition (Two
Experiments)
 Ionic Conductivity at different temperatures (Two
Experiments)
Dr. Kantesh Balani Virtual Lab on Material Response
Apr. 18 2011
Thank You