Metallographic, structural and mechanical characterization of low-density austenitic Fe-Mn-Al-C steels microalloyed with Ti/B and Ce/La in hot-rolling condition

MRS Advances ◽  
2019 ◽  
Vol 4 (57-58) ◽  
pp. 3087-3095
Author(s):  
C.E. Coronado-Alba ◽  
I. Mejía
Keyword(s):  
Grain Size ◽  
Hot Rolling ◽  
Mechanical Characterization ◽  
Research Work ◽  
Distribution Functions ◽  
Second Phase ◽  
Low Density ◽  
Second Stage ◽  
Rolling Condition

ABSTRACTLow-density austenitic Fe-Mn-Al-C steels have high strength, high ductility and a significant weight reduction respect to other alloyed steels. However, this complex system exhibits second-phase precipitation, particularly κ-carbide. It is well-known that the microalloying elements addition to steel generates precipitation hardening, as well as grain refinement effect. It is worth noting that low-density steels can cause cracking during hot-rolling due to high Mn, Al and C contents and segregation in grain boundaries. Hot-rolling conditions play an important role in the dynamic recrystallization mechanisms, and therefore in the austenitic grain size. The main objective of this research work is the metallographic, structural and mechanical characterization of low-density steels microalloyed with Ti/B and Ce/La in hot-rolling condition. For this purpose Fe-(27-30)Mn-(7-8)Al-(1.2-1.8)C (wt.%) low density steels microalloyed with Ti/B and Ce/La were hot-rolled at 1200 °C in two stages. Metallographic, structural and mechanical characterization was carried out by optical (LOM) and scanning electron (SEM) microscopies, electron backscatter diffraction (EBSD) through quality images, inverse pole figures (IPF) and orientation distribution functions (ODF) maps, X-ray diffraction (XRD) and microhardness Vickers (HV) testing. In general, the first stage of hot-rolling exhibits a strongly bimodal microstructure of dynamically recrystallized austenitic grains, while the second stage shows more uniform recrystallized grain size. In the first stage of hot-rolling the austenite is the predominant phase, while in the second stage the α-ferrite phase is barely visible. Low-density steel microalloyed with Ti/B presented better grain size and microhardness values compared to steel microalloyed with Ce/La. Preferred crystallographic orientations were not found.

Metallographic, Structural and Mechanical Characterization of a Low Density Fe-Mn-Al-C Steel Microalloyed with Ti/B in As-Cast and Homogenized Conditions

MRS Advances ◽  
2018 ◽  
Vol 3 (64) ◽  
pp. 3971-3978 ◽  
Author(s):  
O.E. Villanueva-Perez ◽  
I. Mejía ◽  
V. García-García ◽  
A. Bedolla-Jacuinde
Keyword(s):  
Grain Size ◽  
Mechanical Characterization ◽  
The Other ◽  
Low Density ◽  
X Ray Diffraction ◽  
X Ray ◽  
Other Hand ◽  
Average Grain Size ◽  
Cast Condition

ABSTRACTLow density (LD) steels have shown particular characteristics in terms of mechanical properties and microstructure, since they have high strength, high ductility and density reduction up to 18%. On the other hand, the addition of microalloying elements such as Ti and B generate hardening by solid solution and precipitation, as well as grain refinement effect. LD steels generate nano-sized kappa phase precipitated from the austenite matrix, and these advanced steels can reach strength and elongation up to 780 MPa and 60%, respectively. The main objective of this research work is the metallographic, structural and mechanical characterization of a LD steel microalloyed with Ti/B in as-cast and -homogenized conditions. For this purpose a Fe-27Mn-7Al-1.2C (%wt) LD steel microalloyed with Ti/B was melted in a vacuum-induction furnace and cast in metallic mold. LD-Ti/B steel samples were homogenized at 1100 °C during 20, 50, 100, 150 and 200 minutes followed by water quenching. Metallographic, structural and mechanical characterization was carried out by optical (LOM) and scanning electron (SEM) microscopy, X-ray diffraction (XRD) and microhardness Vickers testing (HV10), respectively. In general, results showed a typical dendritic microstructure with average grain size of 1256 μm in the as-cast condition. On the other hand, the as-homogenized condition showed an austenitic equiaxial microstructure with average grain size from 164 to 940 μm. Austenite, ferrite and kappa phases were detected by X-ray diffraction (XRD). Also, second-phase particles such as AlN, TiC and MnS were detected by LOM and SEM-EDS analysis. LD steel microalloyed with Ti/B exhibited the highest microhardness Vickers value (235 HV10) in the as-cast condition, whilst in the as-homogenized condition microhardness gradually decreases from 223 to 198 HV10 as holding time increases.

Fabrication and mechanical characterization of glass fibre reinforced triaxially braided composites

2020 ◽  
pp. 002199832094893
Author(s):  
Gayatri Vineela Marrivada ◽  
Phaneendra Kiran Chaganti ◽  
Ravindran Sujith
Keyword(s):  
Glass Fibre ◽  
Mechanical Characterization ◽  
Research Work ◽  
Braided Composites ◽  
Short Beam ◽  
Beam Shear ◽  
Glass Fibre Reinforced ◽  
The Difference ◽  
Experimental Values

The aim of this research work is to study the mechanical behaviour of dry triaxially braided glass fibre sleeves and its composites experimentally and analytically. The braided glass fibre sleeves for three angles 30°, 45° and 60° were fabricated on a modified maypole vertical braider following a regular braid architecture. Tensile, flexural, short beam shear and impact tests were performed to evaluate the mechanical properties of the composites. A numerical model was developed, which can be used to find the elastic properties and mechanical strength values of the dry braided fabric and its composites. It was observed that the tensile, flexural and interlaminar properties of 30° specimens were more compared to 45° and 60°. The difference between the estimated and experimental values were found to be an average of 8% for tensile moduli and 24% for the tensile strength.

Preparation and Characterization of Fe Doped Bi2Ga4O9 Ceramics

2014 ◽  
Vol 552 ◽  
pp. 283-285
Author(s):  
Huan Huan Chen ◽  
Xiao Yan Zhang ◽  
Xi Wei Qi ◽  
Zhao Jie Zhou ◽  
Gui Fang Sun
Keyword(s):  
Grain Size ◽  
Solid Phase ◽  
Sem Analysis ◽  
Phase Method ◽  
Second Phase ◽  
Doping Content ◽  
Fe Doping ◽  
Sintering Process ◽  
Solid Phase Method

A series of Fe-doped Bi2(FexGa1-x)4O9 (x=0.1,0.2,0.3,0.4,0.5) ceramics were synthesized by solid-phase method with sintering process. The influences of Fe doping content on phase, morphology, dielectric properties are discussed. XRD results show that there is no second phase in Fe-doped Bi2(FexGa1-x)4O9 ceramics. The SEM analysis indicates the grain size of as-prepared doped samples are relatively uniform and estimated to be about 1–4μm. The permittivity of as-prepared doped samples increases and the dielectric loss decrease compared to pure Bi2Ga4O9 ceramics.

The Role of Crystallization of an Intergranular Glassy Phase in Determining Grain Boundary Residual Stresses in Debased Aluminas

1989 ◽  
Vol 170 ◽  
Author(s):  
Nitin P. Padture ◽  
Helen M. Chan ◽  
Brian R. Lawn ◽  
Michael J. Readey
Keyword(s):  
Grain Size ◽  
Grain Boundary ◽  
Residual Stresses ◽  
Glassy Phase ◽  
Analytical Techniques ◽  
Ceramic Materials ◽  
Strength Test ◽  
Second Phase

AbstractThe influence of microstructure on the crack resistance (R-curve) behavior of a commercial debased alumina containing large amounts of glassy phase (28 vol %) has been studied using the Indentation-Strength test. The effect of two microstructural variables, viz. grain size and the nature of the intergranular second phase (glassy or crystalline) has been evaluated. Crystallization of the intergranular glass was carried out in order to generate residual stresses at the grain boundaries, which have been shown to enhance R-curve behavior in ceramic materials. Enhancement of the R-curve behavior was observed with the increase in grain size. However, no effect of the nature of the intergranular second phase on the R-curve behavior, in small and large grain materials, was observed. The results from characterization of these materials using various analytical techniques is presented, together with possible explanations for the observed effects.

Microstructural and Mechanical Characterization of ARB AZ31

2013 ◽  
Vol 765 ◽  
pp. 403-407 ◽  
Author(s):  
Friederike Schwarz ◽  
Katja Lange ◽  
Lutz Krüger ◽  
Rudolf Kawalla ◽  
Stephan Reichelt
Keyword(s):  
Grain Size ◽  
Mechanical Characteristics ◽  
Mechanical Characterization ◽  
Basal Texture ◽  
Electron Backscattered Diffraction ◽  
Roll Bonding ◽  
Average Grain Size ◽  
Twin Roll Cast ◽  
Twin Roll

In this work the influence of accumulative roll bonding (ARB) process on the microstructure and the mechanical characteristic is investigated. Therefore, AZ31 magnesium sheets were successfully deformed through ARB for a maximum of three passes. Twin roll cast sheets and twin roll cast sheets with subsequent heat treatment (480 °C, 1 h) were used as initial materials. After one ARB pass, the highest microstructure changes were measured. Electron backscattered diffraction (EBSD) reveals a bimodal microstructure with an average grain size of ~1µm. In comparison to the initial material a strong basal texture was measured. The significant refinement of grain size after severe plastic deformation cause an increase of tensile and compressive strength, e.g. rising yield stress and ultimate tensile strength of 42% and 15%, respectively. However, the maximum formability remains nearly at the same level. Further ARB passes do not improve the mechanical characteristics further.

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