The Experts below are selected from a list of 684 Experts worldwide ranked by ideXlab platform
H B Mcshane - One of the best experts on this subject based on the ideXlab platform.
-
analysis of high temperature flow stress of titanium alloys imi 550 and ti 10v 2fe 3ai during Isothermal Forging
Materials Science and Technology, 1998Co-Authors: D G C Robertson, H B McshaneAbstract:High temperature flow stress data obtained from laboratory scale Isothermal Forging tests on two titanium alloys, IMI550 (Ti-4Al-4Mo-2Sn-0.5Si) and Ti-10V-2Fe-3Al, have been correlated using a gene...
-
analysis of high temperature flow stress of titanium alloys imi 550 and ti 10v 2fe 3ai during Isothermal Forging
Materials Science and Technology, 1998Co-Authors: D G C Robertson, H B McshaneAbstract:Abstract High temperature flow stress data obtained from laboratory scale Isothermal Forging tests on two titanium alloys, IMI550 (Ti-4Al-4Mo-2Sn-0.5Si) and Ti-10V-2Fe-3Al, have been correlated using a generalised hot working equation. The (α + β) titanium alloy IMI 550 was studied at temperatures in the range 900–950°C, high in the (α + β) phase field, and over a range of strain rates from 4.2 × 10−4 S−1 to 4.2 × 10−2 S−l. The metastable β titanium alloy Ti-10V-2Fe-3Al was studied at temperatures in the range 740–780°C, high in the (α + β) phasefield, and also at 820–950°C in the β field, over the same range of strain rates. A good correlation between the experimental data and the hot working equation was observed for both alloys. Values of the activation energy for hot working have been considered, in conjunction with microstructural evidence, in relation to the dynamic restoration processes taking place. The activation energy for hot working of Ti-10V-2Fe-3Al in the β field has been found to be 185 kJ ...
D G C Robertson - One of the best experts on this subject based on the ideXlab platform.
-
analysis of high temperature flow stress of titanium alloys imi 550 and ti 10v 2fe 3ai during Isothermal Forging
Materials Science and Technology, 1998Co-Authors: D G C Robertson, H B McshaneAbstract:High temperature flow stress data obtained from laboratory scale Isothermal Forging tests on two titanium alloys, IMI550 (Ti-4Al-4Mo-2Sn-0.5Si) and Ti-10V-2Fe-3Al, have been correlated using a gene...
-
analysis of high temperature flow stress of titanium alloys imi 550 and ti 10v 2fe 3ai during Isothermal Forging
Materials Science and Technology, 1998Co-Authors: D G C Robertson, H B McshaneAbstract:Abstract High temperature flow stress data obtained from laboratory scale Isothermal Forging tests on two titanium alloys, IMI550 (Ti-4Al-4Mo-2Sn-0.5Si) and Ti-10V-2Fe-3Al, have been correlated using a generalised hot working equation. The (α + β) titanium alloy IMI 550 was studied at temperatures in the range 900–950°C, high in the (α + β) phase field, and over a range of strain rates from 4.2 × 10−4 S−1 to 4.2 × 10−2 S−l. The metastable β titanium alloy Ti-10V-2Fe-3Al was studied at temperatures in the range 740–780°C, high in the (α + β) phasefield, and also at 820–950°C in the β field, over the same range of strain rates. A good correlation between the experimental data and the hot working equation was observed for both alloys. Values of the activation energy for hot working have been considered, in conjunction with microstructural evidence, in relation to the dynamic restoration processes taking place. The activation energy for hot working of Ti-10V-2Fe-3Al in the β field has been found to be 185 kJ ...
J Shen - One of the best experts on this subject based on the ideXlab platform.
-
microstructural mechanisms during multidirectional Isothermal Forging of as cast ti 6al 4v alloy with an initial lamellar microstructure
Journal of Alloys and Compounds, 2019Co-Authors: Zhen Zhang, A H Feng, J ShenAbstract:Abstract Microstructural evolution and tensile properties of Ti-6Al-4V alloy with an initial lamellar microstructure during the multidirectional Isothermal Forging (MDIF) were investigated. After three steps Isothermal Forging, a homogeneous equiaxed grained microstructure with an average grain size of 1.9 μm was achieved. The grain refinement mechanism included both continuous dynamic recrystallization (CDRX) and discontinuous dynamic recrystallization (DDRX). The necklaces of new DDRX grains with high angle grain boundaries (HAGBs) were formed along the initial β grain boundaries. Grain subdivision was through CDRX. The fraction of recrystallization and the homogeneity of microstructure were improved with the Isothermal Forging steps increasing, the fractions of recrystallization increased from 43% to 63% and the fractions of HAGBs increased from 48% to 71%, respectively. The tensile properties of as-cast Ti-6Al-4V alloy were significantly improved at both room temperature and 400 °C, respectively. The yield strength, ultimate tensile strength and elongation increased 21%, 23%, and 210% at room temperature, respectively. And at 400 °C, the yield strength, ultimate tensile strength and elongation increased 46%, 48%, and 21%, respectively. The fracture mechanism changed from brittle fracture to ductile fracture after the MDIF process.
-
achieving grain refinement and enhanced mechanical properties in ti 6al 4v alloy produced by multidirectional Isothermal Forging
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2017Co-Authors: Zhen Zhang, A H Feng, J ShenAbstract:Abstract This study investigated the principle of multidirectional Isothermal Forging (MDIF) and determined the major microstructural evolution features and unique room-temperature mechanical properties of extra-low interstitial-grade Ti–6Al–4V alloy. The grain refinement mechanism, grain boundary characteristics, and phase transformation during MDIF were explored. After three-step MDIF, a homogeneous microstructure with a grain size of about 0.5 µm was produced. The ultrafine grained Ti–6Al–4V alloy exhibited high yield strength (1170 MPa), high ultimate tensile strength (1190 MPa), and good ductility (10.4%). The mechanism of grain refinement during MDIF included continuous dynamic recrystallization (CDRX) and discontinuous dynamic recrystallization (DDRX). Grain subdivision resulted from CDRX or the transformation of cellular dislocation substructures into new ultrafine grains. The necklace of new DDRX grains formed along the initial grain boundaries of the Ti–6Al–4V alloy. The main strengthening mechanisms were grain boundary and dislocation strengthening. The strength and grain size followed the typical Hall–Petch relationship.
K Suresh - One of the best experts on this subject based on the ideXlab platform.
-
hot Forging of cast magnesium alloy tx31 using semi closed die and its finite element simulation
Materials Science Forum, 2014Co-Authors: K P Rao, K Suresh, Y V R K Prasad, Karl Ulrich KaineAbstract:Magnesium alloys based on Mg-Sn-Ca system have shown improved corrosion and creep properties. In this type of alloys,Sn forms a solid solution with Mg that improves the corrosion resistance while Ca forms thermally stable intermetallic phases in the matrix enhancing the creep resistance. The Sn to Ca ratio is an important variable in deciding the type of intermetallic phases that form in the microstructure.In Mg-3Sn-1Ca alloy (TX31), a single intermetallic phase CaMgSnforms, which is responsible for its improved creep strength.With a view to evaluate its forgeability,Isothermal Forging experiments of TX31 were conducted on a hydraulic press in the temperature range of 350 °C to 500 °C and at speeds of 0.01 mm s-1to 10 mm s-1 using a semi-closed die. Finite-element (FE) simulation of the Forging process was also conducted using the software DEFORM 2D to obtain the local variations of strain and strain rate. The effectivestrain values are below2.4 in the forged components and the Forging loads predicted using FE simulation correlated well with the experimental data for all the Forging conditions. The microstructures of the Forgings show that CaMgSn phase is well distributed in the matrix which exhibited dynamically recrystallized microstructure as predicted by the processing map.
-
anisotropy of flow during Isothermal Forging of rolled az31b magnesium alloy rolled plate in three orthogonal directions correlation with processing maps
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2012Co-Authors: K P Rao, Y V R K Prasad, K SureshAbstract:Abstract A rib-web shape has been forged in AZ31B magnesium alloy rolled plate keeping the Forging direction parallel to the rolling direction (RD), the transverse direction (TD) and the normal direction (ND) with a view to evaluate the anisotropy of flow due to the texture in the plate. Forging was conducted at speeds of 0.01–10 mm s−1 in the temperature range of 300–500 °C under Isothermal conditions. Forging parallel to RD or TD at temperatures lower than about 400 °C produced elliptical cup-shapes with the major axis aligned with TD or RD respectively. On the other hand, Forging parallel to ND at all temperatures resulted in a nearly symmetrical cup-shape. The anisotropy of flow has been attributed to the strong basal texture ({0002} 〈 10 1 ¯ 0 〉 ) in the rolled plate and the dominance of prismatic slip at lower temperatures. At temperatures higher than 400 oC or when forged parallel to ND, pyramidal slip dominates along with cross-slip as the recovery mechanism, which destroys the initial texture and restores the symmetry of flow. The grain size variations for Forgings validated the predictions of the processing maps both in the dynamic recrystallization domains and bifurcations for all the three orientations.
-
materials modeling and simulation of Isothermal Forging of rolled az31b magnesium alloy anisotropy of flow
Materials & Design, 2011Co-Authors: K P Rao, Y V R K Prasad, K SureshAbstract:Abstract Isothermal Forging of a rib–web shape in AZ31B magnesium alloy in the rolling direction was conducted at speeds of 0.01–10 mm s −1 in the temperature range of 300–500 °C with the purpose of validating the results of materials models involving kinetic analysis and processing map. The process was also simulated using finite element method DEFORM to obtain the local values of strain and strain rate. Forging parallel to the rolling direction in the range 375–550 °C and 0.0003–0.3 s −1 under the conditions of dynamic recrystallization (DRX) resulted in a symmetrical cup-shape while at other conditions an elliptical boat-shape was produced with the major axis coinciding with the transverse direction and the minor axis aligned with the normal direction. This anisotropy of flow has been attributed to the strong basal texture in the rolled plate and the dominance of prismatic slip at lower temperatures. In the DRX domain on the other hand, pyramidal slip dominates along with cross-slip as the recovery mechanism, which destroys the initial texture and restores the symmetry of flow. The grain size variation for Forgings done in the DRX domain validated the predictions of the material models.
Zhen Zhang - One of the best experts on this subject based on the ideXlab platform.
-
microstructural mechanisms during multidirectional Isothermal Forging of as cast ti 6al 4v alloy with an initial lamellar microstructure
Journal of Alloys and Compounds, 2019Co-Authors: Zhen Zhang, A H Feng, J ShenAbstract:Abstract Microstructural evolution and tensile properties of Ti-6Al-4V alloy with an initial lamellar microstructure during the multidirectional Isothermal Forging (MDIF) were investigated. After three steps Isothermal Forging, a homogeneous equiaxed grained microstructure with an average grain size of 1.9 μm was achieved. The grain refinement mechanism included both continuous dynamic recrystallization (CDRX) and discontinuous dynamic recrystallization (DDRX). The necklaces of new DDRX grains with high angle grain boundaries (HAGBs) were formed along the initial β grain boundaries. Grain subdivision was through CDRX. The fraction of recrystallization and the homogeneity of microstructure were improved with the Isothermal Forging steps increasing, the fractions of recrystallization increased from 43% to 63% and the fractions of HAGBs increased from 48% to 71%, respectively. The tensile properties of as-cast Ti-6Al-4V alloy were significantly improved at both room temperature and 400 °C, respectively. The yield strength, ultimate tensile strength and elongation increased 21%, 23%, and 210% at room temperature, respectively. And at 400 °C, the yield strength, ultimate tensile strength and elongation increased 46%, 48%, and 21%, respectively. The fracture mechanism changed from brittle fracture to ductile fracture after the MDIF process.
-
achieving grain refinement and enhanced mechanical properties in ti 6al 4v alloy produced by multidirectional Isothermal Forging
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2017Co-Authors: Zhen Zhang, A H Feng, J ShenAbstract:Abstract This study investigated the principle of multidirectional Isothermal Forging (MDIF) and determined the major microstructural evolution features and unique room-temperature mechanical properties of extra-low interstitial-grade Ti–6Al–4V alloy. The grain refinement mechanism, grain boundary characteristics, and phase transformation during MDIF were explored. After three-step MDIF, a homogeneous microstructure with a grain size of about 0.5 µm was produced. The ultrafine grained Ti–6Al–4V alloy exhibited high yield strength (1170 MPa), high ultimate tensile strength (1190 MPa), and good ductility (10.4%). The mechanism of grain refinement during MDIF included continuous dynamic recrystallization (CDRX) and discontinuous dynamic recrystallization (DDRX). Grain subdivision resulted from CDRX or the transformation of cellular dislocation substructures into new ultrafine grains. The necklace of new DDRX grains formed along the initial grain boundaries of the Ti–6Al–4V alloy. The main strengthening mechanisms were grain boundary and dislocation strengthening. The strength and grain size followed the typical Hall–Petch relationship.