ME221 - Structural Materials

ME221 - Structural Materials

Instructor

Alankar Alankar

Section

S2, ASC selected me for this section, however a lot of people played around and shifted from one section to another. There were three sections of which 2 were in the afternoon slots while one was in slot 7. My slot was the latter one, therefore we had to wake up at 8am for the lectures.

Semester

Autumn’19

Course Difficulty

The course was quite theoretical and had a lot of terms which one had to know. However, the numericals were fairly straightforward. A lot of emphasis was given to graphs and diagrams, so it might get confusing. In terms of the theory, the content was easy to follow and was (mostly) directly taken from the reference book.

Time Commitment Required

The time taken would be around 2 hours of self study if one does not want to be piled up with lots of reading material at the end.

Grading

The grading might’ve been harsh because of the density of people near the same score (as a result the grade dropped from AA to BB with a difference of two marks): 9 AAs, 7 ABs, 7 BBs

Attendance Policy

No attendance policy

Pre-requisites

None

Evaluation Scheme and Weightages

So the rough distribution was: Quizzes (4 quizzes, equal weightage) ~ 20%, midsem ~ 25%, endsem ~ 40% and assignments (6 assignments, equal weightage) ~ 15%

Topics Covered in the Course

  • Introduction to Materials Science and Engineering [4 h]
    • The composition- processing- microstructure- properties- performance pyramid
    • The hierarchy of microstructures
    • Metals and alloys, ceramics, polymers and composites
  • Atomic scale structure in solids [7 h]
    • Crystalline and amorphous phases
    • Crystal structure, structural defects, texture (as applicable to metals, ceramics and polymers) 2.3. Atomistic origin of properties and anisotropy
    • Elastic properties
    • Plastic properties (slip and twinning)
    • Strengthening and softening mechanisms
  • Micro scale structure in solids [8h]
    • Thermodynamic equilibrium structures: Phase diagrams and phase transformations
    • Development of structure due to solidification
    • Development of structure due to thermo-mechanical working
    • Thermo-mechanical simulator for high temperature mechanical behavior, property anisotropy
  • Microstructure-Properties-Performance linkage: [6 h]
    • Tension and compression properties
    • Hardness
    • Fracture toughness
    • Fatigue
    • Creep
    • Corrosion
  • Important engineering Materials: In this section, various materials will be taught describing the broad spectrum in each class and principles of material development (structure-property relations) relevant to the particular class [8 h]
    • Steels:
      • Banana diagram and broad classification
      • Various constituent phases
      • Example of one advanced steel
    • Aluminum alloys:
      • Cast and wrought alloys
      • Example of Al-Si cast alloy with grain refiners and modifiers
    • Cu-, Ti- Ni based alloys

Mechanism of instruction and teaching style

Sir used slides for his entire course, with some help from the blackboard for drawing certain diagrams.

Assignments and projects in the Course

The initial assignments (first two) involved analyzing some plots and writing inferences. The following assignments were super simple and only involved a single question. A few words of caution: Sir did not give marks to people who had verbatim copied each others’ assignments. Moreover the grading for these assignments were relative. So if one student in class took extra efforts to explain a one page answer using diagrams and three pages instead, then (s)he would be the benchmark for everyone’s grades.

Exams

So the first two and the fourth quizzes were fairly straightforward and used simple concepts of solid state and some new topics taught in class. It involved analysing diagrams and drawing graphs so it was important to practise them. It consisted of a few theory questions and some numericals (stress-strain calculations, phase diagrams) and so on. The third quiz was MCQ based with multiple correct answers and negative marking. Personally, my marks were terrible, but my previous quizzes compensated for it. Moreover, its weightage was only 5% so you could still make up for it! The midsem had around 6-7 questions of which one question was incorrect so we had all gotten a bonus for it. However, the prof gave an additional bonus for those who “assumed” the right question and solved it. There were two questions which were from the same slide and a lot of us had skipped it because there was a single diagram with seemingly trivial text. So again, as I mentioned before, do not skip diagrams and text. If you roughly know a diagram, developing the skill to explain it in long paragraphs would definitely help.

The endsem was also along similar lines, where the prof asked for several diagrams. Some questions were reasoning based and you would have to know the concept very well in order to explain it. They would specifically look for certain keywords while grading you. Again, there was a slide that many of us skipped but it came as a question with 1/10th of the total marks. Phase diagrams were emphasised. The content covered in the later half of the course had more weightage!

The prof would let us have a cheat sheet with formulae only, so there would be no need to memorise the formulae.

TLDR: Graphs and diagrams are a must

Reference Material

Callister was the most important one amongst these, and I’d say the examples were very useful because the questions would be along those lines. Sir’s slides were also primarily based on Callister.

  • W D Callister, Materials Science and Engineering, An Introduction (Wiley Publication)
  • David R Askeland and Pradip P Phule, The science and Engineering of Materials (Cengage Learning), Physical Principles of Electron Microscopy: An Introduction to TEM, SEM, and AEM, Springer, 1st ed. 2005R
  • Mechanical Metallurgy, George E Dieter, McGraw Hill, 2017

Importance of Course

The course is useful for anyone interested in material sciences and fabrication of new materials. The course is a preliminary one for molecular simulations and other analyses.

Anything else relevant to the course

Well a lot of us have gotten out of the habit of giving descriptive answers and explaining our points across appropriately. So redeveloping that skill for this course would definitely help you bag a good grade!

Review by: Bhavini Jeloka