Internal Friction on AISI 304 Stainless Steels with Low Tensile Deformations at Temperatures between−50 and 20C

Abstract

Austenitic stainless steels specimens were deformed by tension in temperatures in the range of −50 • C to 20 • C and 0.03 to 0.12 true strain, in order to obtain different volumetric fractions of ε (hexagonal close packed) and α (body centered cubic) strain induced martensites. The morphology, distribution and volumetric fractions of the martensites were characterized by metallography and dilatometry analysis and quantified by ferrite detector measurements. The damping behavior of specimens with different volumetric fractions of martensites was studied in an inverted torsion pendulum in the 40 • C to 400 • C range. The εand α -martensites reversion was observed in the temperature range of 50 • C-200 • C and 500 • C-800 • C, respectively, by dilatometry. Internal friction curves in function of temperature of the deformed samples presented internal friction peaks. The first internal friction peak is related to sum of the amount of εand α -martensites. For low deformations it aligns around 130 • C and it is related only to the ε → γ reverse transformation. The peak situated around 350 • C increases with the specimen degree of deformation and is, probably, related to the presence of α /γ interfaces, and deformed austenite.

Effect of Warm Rolling and Annealing on Microstructure, Texture, and Mechanical Properties of a 2205 Duplex Stainless Steel

“…α 0 , ε-martensite can act as an intermediate phase during the transformation of γ into α 0 . [38,47,[51][52][53] Studies done by Guo et al [32] , Soares et al, [39] and De et al [50] revealed that the reduction in the work hardening rate decay can be associated with α 0 -martensite formation in the microstructure with the progress of deformation. Therefore, in stage II, the deformation-induced phase transformation is probably the mechanism responsible for the hardening of the material.…”

Temperature dependent measurement of internal damping of austenitic stainless steels

“…3. Metallographic analysis of longitudinal cross-section of the specimen in initial state after chemical etching in HNO 3 +HF+glycerine solution showed that the structure is non-homogeneous and have polyedric austenite grains with different grain sizes and occurrence of annealing twins and deformation martensite after plastic deformation as a result from the final treatment. In the case of AISI 316Ti titanium carbides TiC where present in the structure.…”

“…The internal damping can be defined as the capacity of a material to damp mechanical vibrations. The capacity change of material to damp mechanical vibrations as function of time or temperature corresponds to a structural, microstructural and substructural change [3][4][5].…”

Desenvolvimento de sistema de apoio com depósito cerâmico para soldagem e processamento por atrito com pino não consumível

“…Uma microestrutura formada por frações aproximadamente iguais de ferrita e austenita proporciona aos AIDs alta resistência ao trincamento por corrosão-sob-tensão, corrosão localizada e uma resistência mecânica superior a dos aços inoxidáveis austeníticos convencionais (AIA), combinada a uma boa tenacidade [22]. Embora, os AIAs continuem sendo objeto de continuados estudos devido a sua conformabilidade, uma das mais demandadas propriedades deste tipo de aço em aplicações industriais [23,24].…”