Crystal Structure & Iron-Carbon Diagram PYQs | Material Science Part 1 | S K Mondal Sir

🎯 GATE 2027 subscription: https://unacademy.com/goal/Gate/QGFRK... Referral code: KHUSHRAHO Material Science one shot through PYQs for GATE 2027 Mechanical Engineering (ME), Production (PI) and ESE, Part 1, live with S K Mondal Sir (Ex-IES). Crystal structures (SC, BCC, FCC, HCP), number of atoms, coordination number, atomic packing factor, density of unit cells, crystal systems and Bravais lattices, Miller indices, crystal defects and dislocations, slip systems, and the complete iron-carbon diagram with the lever rule, all learned by solving previous year GATE questions with easy memory tricks. 👉 Part 2 (Heat Treatment & Alloys): https://www.youtube.com/live/FxQJkAjG... Unaacdemy GATE Scholarship Test - https://unacademy.com/scholarship/UGS... Useful for: GATE ME & PI, ESE, ISRO, BARC, PSUs, SSC JE and RRB JE. ⏱️ Chapters 0:00 Welcome: Material Science Through PYQs 0:52 Crystalline vs Amorphous Materials 3:24 Crystal Structure & Diffraction Pattern 5:10 Rock Salt Example 6:00 Amorphous: No Long-Range Order 7:47 Hard Sphere Model 9:32 Lattice vs Model: The Biggest Doubt 11:19 Important Table: SC, BCC, FCC & HCP 13:11 Number of Atoms per Unit Cell 16:35 Body-Centred Cubic: 2 Atoms 18:17 Face-Centred Cubic: 4 Atoms 19:08 Coordination Number 20:54 Simple Cubic: Coordination Number 6 22:38 Hexagonal Close Packed (HCP) 25:11 Coordination Number 12 for FCC & HCP 27:49 a/r Relations for SC & BCC 29:37 FCC: a/r Relation 31:22 HCP: c/a = 1.633 32:12 Atomic Packing Factor 33:02 Volume of the Unit Cell 38:43 APF: FCC & HCP 0.74, BCC 0.68 40:26 PYQ: Match Crystal Structure with Packing Fraction 42:10 Memory Trick for BCC Metals 44:47 Memory Trick for FCC Metals 46:34 Memory Trick for HCP Metals 49:12 GATE vs ESE Syllabus Focus 51:01 PYQ: Which Metal Is FCC? 52:49 Elimination Strategy 54:31 Ionic Radius: Don't Memorise 55:23 NaCl & ZnS Structures 57:12 SI vs CGS Units Trap 58:02 Avogadro Number in SI Units 59:45 Density of a Cubic Unit Cell 1:04:59 Density Formula: ρ = nM / (a³ Nₐ) 1:07:42 HCP Unit Cell Volume 1:08:04 Diamond Cubic Structure 1:14:57 PYQ: Density Calculation 1:18:36 PYQ: Lattice Parameter of an FCC Metal 1:22:53 Seven Crystal Systems 1:23:45 14 Bravais Lattices 1:25:30 Trick to Remember Them 1:29:34 Break (Skip to 2:46:09) 2:46:09 Session Resumes 2:47:59 PYQ: High-Speed Steel & Tungsten 2:52:50 Graphite Flakes in Cast Iron 2:53:41 Miller Indices: Directions 2:56:16 Family of Directions & Planes 2:57:06 Miller Indices for Planes 2:59:49 PYQ: Crystal Defects 3:02:26 Point, Line, Surface & Volume Defects 3:03:22 Substitutional & Interstitial Defects 3:05:57 Schottky & Frenkel Defects 3:08:28 Edge & Screw Dislocations 3:09:24 Cross Slip 3:11:05 Slip Systems: FCC Has 12 3:12:47 Cold Working & Strain Hardening 3:13:31 PYQ: What Causes Fracture? 3:14:38 Iron-Carbon Equilibrium Diagram 3:19:31 Maximum Carbon: 6.67% 3:21:14 Hypo- & Hyper-Eutectoid Steels 3:22:17 Eutectic & Eutectoid Reactions 3:24:02 Pearlite: Ferrite + Cementite 3:25:46 Eutectic Point: 1147°C & 4.3% C 3:29:16 Peritectic Point: 1495°C 3:30:10 Critical Temperatures: 723, 910, 1400 & 1536°C 3:35:20 Alpha Iron (BCC) vs Gamma Iron (FCC) 3:37:02 Microstructures: Ferrite & Austenite 3:40:37 Pearlite Forms at 0.8% Carbon 3:43:14 Microstructure of Hypo- & Hyper-Eutectoid Steel 3:44:57 PYQ: Microstructure Above the Eutectoid Temperature 3:46:39 PYQ: Phases & Structures 3:48:24 Invariant Reactions 3:50:05 PYQ: Eutectoid Reaction 3:53:39 Isomorphous & Peritectic Systems 3:54:34 Solidus, Liquidus & Solvus Lines 3:55:26 Solder: A Eutectic Alloy 3:56:18 Lever Rule 3:59:53 PYQ: Lever Rule: Fraction of Liquid & Solid 4:04:11 PYQ: Fraction of Solid 4:06:53 PYQ: Temperature for a Given Composition 4:10:27 PYQ: Fraction of Pearlite 4:13:07 How the Examiner Changes the Question 4:15:42 Pearlite Is a Mixture of Ferrite & Cementite 4:17:27 Proeutectoid Cementite 4:23:43 PYQ: 0.83% Carbon Steel 4:28:15 Ferrite Fraction Inside Pearlite 4:31:41 The Concept Behind the Lever Rule 4:33:26 PYQ: 1.5% Carbon Steel 4:37:54 When It's 100% Pearlite 4:42:17 PYQ: Cooling from 1000°C: Proeutectoid Fraction 4:44:50 750 Lectures & Course 4:50:09 Solid Solutions: Brass 4:50:59 The Two Most Important Chapters 4:51:53 Closing 📅 Plan your GATE preparation: 🗓️ Free Personalised Study Planner for GATE 2027 & 2028: https://unacademy.com/content/gate/fr... 📝 MahaSangram Test Series for GATE 2027 (ME): https://unacademy.com/store/test-seri... 📚 More Material Science: Crystal Structure Tricks: BCC, FCC, HCP Examples:    • Crystal Structure Tricks: BCC, FCC, HCP Ex...   📚 Material Science for GATE & ESE Playlist:    • Material Science for GATE Mechanical & ESE...   📢 Telegram: https://t.me/skmondalmaa