Low-Temperature Mechanical Behavior of Super Duplex Stainless Steel with Sigma Precipitation

Abstract

Experimental studies in various aspects have to be conducted to maintain stable applications of super duplex stainless steels (SDSS) because the occurrence rate of sigma phase, variable temperature and growth direction of sigma phase can influence mechanical performances of SDSS. Tensile tests of precipitated SDSS were performed under various temperatures to analyze mechanical and morphological behavior.

Effects of Heat Input on Microstructure, Corrosion and Mechanical Characteristics of Welded Austenitic and Duplex Stainless Steels: A Review

“…As the annealing temperature increases, the volume fraction of austenite decreases, and the ferrite must take up more nitrogen in the solid solution. Although these levels of nitrogen are soluble in ferrite at high temperatures, Cr2N precipitates in the ferrite upon rapid cooling because nitrogen is relatively High toughness can be obtained by implementing suitable solution temperatures and cooling rates [61][62][63]. This finding is consistent with a previous report [64] indicating that the optimal solution temperature and cooling rate result in high toughness.…”

“…Moreover, such deposition can reduce the toughness of DSS and SDSS [56][57][58][59][60]. High toughness can be obtained by implementing suitable solution temperatures and cooling rates [61][62][63]. This finding is consistent with a previous report [64] indicating that the optimal solution temperature and cooling rate result in high toughness.…”

Advanced Mechanical Strength in Post Heat Treated SLM 2507 at Room and High Temperature Promoted by Hard/Ductile Sigma Precipitates

“…This creates very high stacking fault energies (SFE) which is higher than the bond energies holding the atoms together, causing brittleness [21]. Low plasticity (lower than 4%) was reported by Kim et al [28], where the mechanical behaviour of duplex stainless steel containing sigma precipitates were studied. Hau et al [29] investigated the sigma phase embrittlement and reported that the presence of sigma phase in stainless steel resulted in loss of ductility and toughness at room temperature.…”

Effect of the Temperature in the Mechanical Properties of Austenite, Ferrite and Sigma Phases of Duplex Stainless Steels Using Hardness, Microhardness and Nanoindentation Techniques

“…However, its main drawback is the tendency to form detrimental phases at temperatures between 600 • C and 900 • C, being the cause of a significant loss of toughness and resistance to localized corrosion. One of the most known and representative detrimental phases is the precipitation of the sigma phase (σ), a Cr-and Mo-rich intermetallic compound [12][13][14][15][16][17][18][19][20][21]. This σ phase shows a tetragonal crystallographic structure with 32 atoms per unit cell [22] making possible a considerable increase in the resultant hardness, whereas a decrease in the toughness as well as elongation is also observed [23][24][25][26][27].…”