Análisis de la Tenacidad a la Fractura Elasto-Plástica en Aceros TWIP 22Mn-0,6C-xCr

Abstract

Over the past decades, high manganese TWIP steels have become one of the metallic materials that have received special attention for research due to their most relevant characteristic, which corresponds to an excellent combination of high mechanical strength with great ductility. These properties are attributed to the formation of mechanical twinning. Currently, research has extensively studied the effect of alloying elements such as C, Al, and Si. It is emphasized that the focus should be on finding TWIP alloys with an appropriate chromium content that acts as a potential substitute for austenitic stainless steels. On the other hand, among the numerous studies conducted recently, it is noted that the fracture properties of these steels have not been thoroughly analyzed. This graduation thesis aims to analyze the fracture toughness property of TWIP steels Fe-22Mn-0.6C, Fe-22Mn-0.6C-5Cr, and Fe-22Mn 0.6C-10Cr with a thermo-mechanical treatment of forging, homogenization, and quenching. Chemical and microstructural characterization of the alloys was carried out through optical metallography, grain size measurement, and determination of the stacking fault energy by X-ray diffraction. Subsequently, tensile and hardness tests were conducted at room temperature to determine the effect of chromium on some mechanical properties. Finally, fracture toughness tests were performed according to ASTM E1820, using the basic and normalization methods with C(T) specimens to determine the initiation parameter JIC. The obtained values of this parameter were correlated with the chromium percentage of the alloy. In general, the alloys exhibited excellent crack propagation toughness, where the steel containing 5% wt. of chromium showing the highest JIC value of 892 [kJ/m2 ].