SHEET 04 — PAST ULTIMATE

How It Breaks

Past ultimate, on the descending branch. Six words, six stations.

• 16Ductile Overload4 min readThe honest failure: too much load through a material doing exactly what it said it would. What it leaves behind — necking, a dimpled surface, visible warning — and why it is the failure engineers prefer.
• 17Brittle Fracture7 min readNo stretch, no warning, no second act. What changes a material from ductile to brittle, the flat bright surface with its chevron markings pointing home, and the historical failures that made the mechanism famous.
• 18Fatigue Cracking6 min readBeach marks on a fracture face record a crack's whole history — where it started, how long it worked, how it finished. Reading a fatigue surface, and why the final overload is the smallest part of the story.
• 19Buckling3 min readFailure by geometry rather than by strength: a column that was strong enough but not straight enough. Slenderness, end conditions, and why buckling can happen far below the material's capacity.
• 20Creep3 min readAt temperature, time joins the load case. The slow exchange of shape for survival, where creep governs, and why a component can fail without the load ever changing.
• 21Stress-Corrosion Cracking5 min readA material, a stress and an environment — each harmless alone, dangerous together. Fine branching cracks, hard to see and easy to miss on inspection, and the specific combinations that cause it.