Answer Happy

Problem #3 (20 points): There are six different engineering stress-strain diagrams (a, b, c, d, e and f) shown below. One of the stress-strain diagrams is for alloyed steel with 0.77% carbon content where this alloy is cooled slowly (to maintain equilibrium) from austenite phase, let's say it's cooled down slowly from a temperature of 1100 C to room temperature (lets name this alloy P). One of the other diagrams is for alloyed steel with 0.77% carbon content (Same carbon content as alloy P) where this alloy in the austenite phase is cooled at high rate such as oil quenching, let's say from a temperature of 1100 C quenched in oil and martensite is mainly formed (let's name this alloy M). The diagram for alloy P is shown below. Qualitatively guess which of the six stress-strain diagrams shown below refers to alloy pure iron (Ferrite with no heat treatment or work hardening) and which of them refers to alloy M? (Stress) с a Alloy P b d € (Strain)