Correlation between microstructure and intergranular corrosion behavior of low delta-ferrite content AISI 316L aged in the range 550e700 C
TypeArticles dans des revues avec comité de lecture
The microstructure and the phase identification of austenitic stainless steel AISI 316L with low δ-ferrite content (δ ≤ 1%) and aged for up to 80 000 h at temperatures ranging from 550 to 700 °C were investigated by using an optical microscope (OM), a scanning electron microscope (SEM) and a transmission electron microscope (TEM). Local changes of chromium content, resulting from nucleation and growth of chromium-rich phases during aging, were quantitatively assessed by energy dispersive X-ray spectroscopy (EDX) in the scanning transmission electron microscope (STEM). The intergranular corrosion behavior (IGC) of annealed and aged specimens was evaluated using the double loop electrochemical potentiokinetic reactivation (DL-EPR) and completed by IGC morphologies according to the ASTM A262 practice A standard. The results showed that δ-ferrite decomposed gradually into M23C6 at 550 °C and decomposed totally into intermetallic phases (σ, η, χ, and R) and into secondary austenite (γr) at temperatures equal to or higher than 650 °C. Similarly γ-austenite decomposed into M23C6 carbide at 550 °C and into intermetallic phases such as η and σ in addition to carbide, at higher temperatures. The time-temperature-sensitization diagram (TTS) was established and used to calculate the critical cooling rate (CCR) that prevents IGC sensitization. The analysis of IGC results leads to the conclusion that sensitization-desensitization is still controlled by the characteristics of chromium-depleted area surrounding austenite grain boundary regions. No significant effect of remained δ-ferrite and derived components on the corrosion behavior of AISI 316 L containing 1% of δ-ferrite.
Showing items related by title, author, creator and subject.
Potential fatigue strength improvement of AA 5083-H111 notched parts by wire brush hammering: Experimental analysis and numerical simulation SIDHOM, Naziha; BEN MOUSSA, Naoufel; JANEB, Sameh; BRAHAM, Chedly; SIDHOM, Habib (ELSEVIER, 2014)The effects of milling as machining process and a post-machining treatment by wire-brush hammering, on the near surface layer characteristics of AA 5083-H111 were investigated. Surface texture, work-hardening and residual ...
YAHYAOUI, Houda; BEN MOUSSA, N; BRAHAM, Chedly; SIDHOM, H; BEN FREDJ, N (Wiley, 2015)Machining defects as rebuilt material and dislodgement were often induced by cutting of difficult to machining AISI 304 stainless steel. Their density increases with a decreasing of cutting speed. The effect of these defects ...
Assessment of low cycle fatigue improvement of machined AISI 316 stainless steel by brush hammering SIDHOM, N; MAKHLOUF, K; KHLIFI, A; BRAHAM, Chedly; SIDHOM, H (Wiley, 2014)The effects of wire brush hammering on low cycle fatigue behaviour of AISI 316 austenitic stainless steel has been investigated on turned samples through an experimental study combining strain controlled fatigue tests, ...