Mechanical properties of machined components are controlled by inducing phase transformations in the outer layer of the materials. Induction hardening is one such manufacturing process where the surface hardness is enhanced while the core is retained with the original structure and characteristics. In this study, a mathematical model had been developed to predict the hardness and the volume fra...

A generalized phase transformation kinetics model is used to understand the martensite to austenite transformation in a cold-rolled and annealed metastable AISI 301LN ultrafine-grained austenitic stainless steel. The model shows that the presence of interstitial nitrogen and heavy cold-rolling is important to promote fast transformation kinetics, through rapid nitrogen-diffusion and austenite n...

In this paper, the effect of thermomechanical loading on the behavior of deflection-based harvested energies from a shape memory polymer system is experimentally investigated. Samples are created with honeycomb cells from poly-lactic acid using additive manufacturing techniques. The shape memory effect in shape recovery and force recovery paths are studied under thermomechanical tests in bendin...

We have investigated the possibility of producing a magnetic encoder by an innovative process. Instead of turning grooves in the encoder bar for precise positioning, we incorporated the information in 304L stainless steel by transforming the austenite to martensite after bar extrusion in liquid nitrogen and marking it with a laser, which caused a local transformation of martensite back into aus...

in this research, graphitization transformation of a commercial hypereutectoid steel called ck100 was studied by the dilatometric experiments at the range of 600 – 700 °c from prior martensitic structure. also the effect of quenching media on the initial graphitization time and completion of transformation has been discussed. also, graphitization transition from the different prior microstructu...

The influence of the free surface on martensitic transformation was examined by comparing the highest temperature at which martensite forms (MS), as measured using dilatometry, with surface–observations using confocal laser scanning microscopy. It is found that the proximity of the surface during confocal microscopy permits martensitic transformation to occur at a higher temperature, with a red...

The Ginzburg-Landau theory for multivariant martensitic phase transformations is advanced in three directions: the potential is developed that introduces the surface tension at interfaces; a mixed term in gradient energy is introduced to control the martensite-martensite interface energy independent of that for austenite-martensite; and a noncontradictory expression for variable surface energy ...

A series of medium-carbon low alloy steels was quenched to martensite and tempered at 150 C. This low-temperature-tempered (LTT) martensite was subjected to uniaxial tensile and impact testing. Yield and ultimate tensile strength and uniform elongation increased, and post uniform and total elongation and fracture toughness decreased, with increasing carbon concentration. The carbon dependence o...

Besides permitting an accurate determination of the ferromagnetic-to-paramagnetic phase transition temperature and the characteristic temperatures for the beginning and end of the growth of martensite (austenite) phase at the expense of austenite (martensite) phase while cooling (heating), the results of an extensive ac susceptibility, sound velocity and internal friction investigation of the t...

Dual phase (DP) steels have high strength, while maintaining outstanding elongation capacities. This is possible using a well-controlled thermomechanical process that produces perfect combination in the DP microstructures. However, automotive makers are required to weld steels, which generates soft zone microstructure. In this work, 1.6 mm-thick DP980 steel sheets were welded by gas metal arc w...