Question

Testing temperature, "C 4. How is the energy absorption increased improved fracture toughness) in Steels? Describe ow (see Figure 8.3). (a) Would you use 2%Mn or 0%Mn to improve the fracture toughness of the steel. (b) Should the ductile brittle transition temperature be high or low in steel to resist fractures? (C) Do you think there is dislocation motion during these experiments? If so, fast or slow? a) 27 I b ) low C. fast. O 25 Temperc 10

Answer 1

Solution Energy absortion (Fractuve Toughnew) is the Property which deseribes the qbility of the material 4. to resist facture nd is one of th most impotant properties It is the amount of Energy that the matenal can absorb be fre fracture. fracture Toughe ss Modulus is represen ted by th area under the curre a-fter the Elaste Limit to the Fracture Point T stress C shaded Region Represents Modulus of Toughness strain arca of sha ded Thus for steel , the mor the the qraph curre needs to shift t ight the move hand sid., hen ce the move for ower the strain rate steis rates

Ca) Thus toimprove "the fractūn Toughnerr of steel, I would de-fnitely Pre-fer 27. Mn to be added as this increases the area under the urve thus and CUrve is shifting towards left of the qraph of stesr strcun Curve Even on the graph proided in queston for Impact Energy V Tempeature Eneray is absor bed by 27 Mn addition as ompared to move Impact i can b Seen that O Mn (b) The moe the materia| is ductile the is the move fra cture toughness If the material trans-forms int brittle phase, te fractūr t ugh ne ss reduces Hence to incre ase fractue tuqhness , it is pre ferred t hare the material in the 2on of ductiliby as long as possi ble At low temper atu res it the matenal can be Se en that retains its state of ductility fer longer durations and doe sn't trans form int brittHe phase Wwlile at higher temperatur, the steel trans forms int brittle phase tvo be comes harde ned. Hence low temperature is easily as always pre ferred for high fractue toughness value Co Yeah, a-fast vate of dis lo cafion mobien is observed thoughout the experiment As the values of Impact stengt hiqhly flenible and fluctu ates with a small an temperabe cha nge Tha fluctuation is in one dircdion and are its temendous

Conclusion - Fracture Toughness is one of the most important property due to which steel is preferred in many applications. It is the ability of absorbing energy. More the material stays in ductility zone, more is the fracture toughness. Do upvote and comment if more clarification is required for the subject.