On the microstructure and strengthening mechanism in oxide dispersion-strengthened 316 steel: A coordinated electron microscopy, atom probe tomography and in situ synchrotron tensile investigation

Abstract

a b s t r a c tAn oxide dispersion-strengthened (ODS) 316 steel was developed to simultaneously provide the advantages of ODS steels in mechanical strength and radiation tolerance as well as the excellence of austenitic steels in creep performance and corrosion resistance. The precipitate phases within the austenite matrix were identified by the combined techniques of atom probe tomography (APT), scanning transmission electron microscopy equipped with electron dispersive X-ray spectroscopy (STEM-EDS), and synchrotron wide-angle and small-angle X-ray scattering (WAXS and SAXS). Coarse TiN, hexagonal YAlO 3 and orthorhombic YAlO 3 precipitates were found along with fine Y-Ti-O nanoparticles. In situ WAXS experiments were performed at room and elevated temperatures to examine the size effect on the load partitioning phenomenon for TiN, hexagonal YAlO 3 and Y 2 Ti 2 O 7 phases. In addition, the dislocation density evolution throughout the tensile tests was analyzed by the modified Williamson-Hall method and confirmed by transmission electron microscopy (TEM) observations, revealing the difference in plasticity at various temperatures.

Austenitic Oxide Dispersion Strengthened Steels : A Review

“…Figure 3 shows APT of clusters in ODS316 steel. The figure indicates that the clusters are Y-Ti-Al-O type 11 .…”

“…Austenitic ODS steels are made with different grades of austenitic stainless steel like 304 2,4-9 , 310 5,10 , 316 [11][12][13] , 316 L 3 with different percentages of Y 2 O 3 and Ti as dispersoids. The MA parameters lie in the range of BPR 5:1 to 10:1, speed 300 RPM -600 RPM, and MA of these alloys is usually carried out up to 100 hours depending on the milling conditions.…”

“…The MA parameters lie in the range of BPR 5:1 to 10:1, speed 300 RPM -600 RPM, and MA of these alloys is usually carried out up to 100 hours depending on the milling conditions. The reported consolidation parameters are 50 MPa to 100 MPa pressure with sintering temperature in range of 900 °C -1100 °C and holding time of about 5 min -15 min [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] …”

“…There are different techniques used to characterise the clusters such as Z contrast mode, high angle annual dark field (HAADF), electron energy loss spectroscopy (EELS) and energy dispersive spectroscopy (EDS) 4,11 attachments in transmission electron microscope (TEM) [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] , synchrotron x-Ray diffraction and atom probe tomography (APT) 4,11,15 . The APT, EELS, and EDS are used to analysis the chemical composition of the dispersoids.…”

“…The yield strength and ultimate tensile strength of the austenitic ODS steels at room temperature ranges from 380 MPa -852 MPa 3,4,9,11 and 650 MPa -1000 MPa, respectively 3,4,7,8,10,11 . At 500 °C, the yield strength of these steels ranges from 230 MPa -440 MPa 3,7,8,10,11 . Similarly, at 700 °C the yield strength ranges from 230 MPa -300 MPa 3,9 .…”