Alpha phase precipitation in Ti-30Nb-1Fe alloys – phase transformations in continuous heating and aging heat treatments

2016 ◽  
Vol 677 ◽  
pp. 222-229 ◽  
Author(s):  
Fernando Henrique da Costa ◽  
Camilo A.F. Salvador ◽  
Mariana G. de Mello ◽  
Rubens Caram
Keyword(s):  
Phase Transformations ◽  
Alpha Phase ◽  
Heat Treatments ◽  
Continuous Heating ◽  
Phase Precipitation

Effect of boundary on the alpha phase precipitation in a near-alpha titanium alloy

2018 ◽  
Vol 233 ◽  
pp. 298-301 ◽  
Author(s):  
Xiongxiong Gao ◽  
Weidong Zeng ◽  
Xin Li ◽  
Dadi Zhou ◽  
Jianwei Xu ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Alpha Phase ◽  
Phase Precipitation ◽  
Alpha Titanium

scholarly journals Structural Investigations of Solidification and Heat Treatments Influence on High Alloyed Cast Irons Grades with Nb-V-Ti Additions

2009 ◽  
Vol 289-292 ◽  
pp. 77-86 ◽  
Author(s):  
Jacqueline Lecomte-Beckers ◽  
Jérôme Tchoufang Tchuindjang
Keyword(s):  
Phase Transformations ◽  
Volume Fraction ◽  
Raw Materials ◽  
Solidification Process ◽  
Heat Treatments ◽  
Hot Strip Mill ◽  
Cast Irons ◽  
Structural Investigations ◽  
Alloyed Cast ◽  
The Matrix

Two High Alloyed Cast Irons (HACI) were studied, both belonging to the Fe-C-Cr-Si-X system where X represented a strong carbide forming element. One of these alloys was obtained after adding Nb, V and Ti to the chemical composition of the other alloy. Raw materials originated from spun cast rolls for hot strip mill were submitted to different heat treatments routes, in order to study the influence of alloying elements on the microstructure. Both HACI grades contained a mixture of martensite and retained austenite matrix in the as-cast conditions and after quenching. Differential Thermal Analysis was carried out on the heat treated samples in order to determine the phase transformations occurring during re-melting and subsequent solidification sequence. Diffusionless transformations leading to various types of martensite were found in the matrix. Bulky NbC carbides precipitating at the beginning of the solidification process strongly influence the nature and the rate of the subsequent diffusional phase transformations, particularly for HACI grade with Nb, V and Ti additions. Quantitative metallography was done to determine graphite, NbC carbides, cementite and matrix volume fraction in HACI studied grades.

scholarly journals In-Situ Characterization by High-Energy X-ray Diffraction of the Phase Transformations Leading to Transformation-Induced Plasticity-Aided Bainitic Steel

2019 ◽  
Vol 3 (4) ◽  
pp. 25
Author(s):  
Zélie Tournoud ◽  
Frédéric De Geuser ◽  
Gilles Renou ◽  
Didier Huin ◽  
Patricia Donnadieu ◽  
...  
Keyword(s):  
Carbon Content ◽  
Phase Transformations ◽  
High Energy ◽  
Heat Treatments ◽  
Treatment Temperature ◽  
Bainitic Steel ◽  
X Ray Diffraction ◽  
Transformation Induced Plasticity ◽  
X Ray

The phase transformations occurring during the heat treatments leading to transformation-induced plasticity (TRIP)-aided bainitic steel have been investigated in-situ by high-energy X-ray diffraction (HEXRD) conducted with synchrotron light at 90 keV. Direct microstructure characterization has been performed by electron microscopy using electron backscatter diffraction and orientation and phase mapping in a transmission electron microscope. HEXRD data allow the quantification of the evolution of the austenite phase fraction with the heat treatments, as well as its carbon content and the fraction of carbides, from the lattice parameter evolution. It is shown that different combinations of austenite fraction and carbon content can be reached by adjusting the heat treatment temperature.

Study of the Columnar Grain Growth in IF Steels during Continuous Heat Cycles

2010 ◽  
Vol 638-642 ◽  
pp. 3284-3290
Author(s):  
Wlodzimierz Kaluba ◽  
T. Kaluba
Keyword(s):  
Temperature Gradient ◽  
Phase Transformations ◽  
Continuous Heating ◽  
Air Cooling ◽  
Cooling Period ◽  
Heating And Cooling ◽  
Columnar Grains ◽  
Interface Displacement ◽  
Geometrical Form ◽  
Columnar Grain

The growth of columnar grains in fully recristallized IF steel during rapid heat cycles was examined experimentally. The heat cycles consisted of continuous heating with a rate up to 1500°C/s followed by water or air cooling. The employed heating method, as well as the geometrical form of the samples, enabled to obtain the temperature gradients up to 2000°C cm-1. Moreover, temperature measurements and recordings with the aid of ultra-rapid infrared pyrometry made it possible to determine the characteristic temperatures of phase transformations taking place during heating and cooling periods. The main key parameters of the columnar growth, including temperature gradient and the displacement rate of isotherms corresponding to ferrite-austenite and austenite-ferrite phase transformations could also be examined. The results show that the growth of columnar grains already starts at the heating stage at the ferrite/austenite interface moving against the temperature gradient. During the air cooling period, the growth is taking place according to the temperature gradient, together with the austenite/ferrite interface displacement. It was suggested that columnar-like morphology development occurs according to a selective growth mechanism.

scholarly journals Phase transformations during continuous heating: effect of Sn addition on the microstructure of Ti-13Mo alloy

2020 ◽  
Vol 321 ◽  
pp. 05017
Author(s):  
M.G. de Mello ◽  
F.H. da Costa ◽  
R. Caram
Keyword(s):  
Lattice Parameter ◽  
Continuous Heating ◽  
Phase Precipitation ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
Β Phase ◽  
Ω Phase ◽  
Α Phase ◽  
Heat Treated ◽  
Kinetics Of

The addition of Sn to the Ti-Mo system can diminish the formation of ω phase and slow down the precipitation kinetics of α phase due to the low atomic diffusivity of Sn atoms in Ti. To explore α phase precipitation in Ti-13Mo and Ti-13Mo-6Sn (wt.%) alloys, differential scanning calorimetry (DSC) was applied using different heating rates to determine ω phase dissolution, α phase precipitation and β transus temperatures. The DSC results were then used to determine the aging heat treatment temperatures. Samples were heat-treated at 600 °C for 1 h and 24 h to examine microstructure features. The addition of Sn to Ti-13Mo alloy was found to increase the β phase lattice parameter, increasing β transus temperatures and resulting in microstructures with heterogeneous and coarser α phase precipitation.

Substructural-Phase Transformations during Heat Treatments of the Ti–50.9 at % Ni Nanocrystalline Alloy

2018 ◽  
Vol 44 (12) ◽  
pp. 1120-1123
Author(s):  
T. M. Poletika ◽  
S. L. Girsova ◽  
A. I. Lotkov ◽  
K. V. Krukovskii
Keyword(s):  
Phase Transformations ◽  
Nanocrystalline Alloy ◽  
Heat Treatments

scholarly journals Prediction of microstructure composition in steel plate heated using high power Yb:YAG laser radiation

2019 ◽  
Vol 254 ◽  
pp. 02023
Author(s):  
Marcin Kubiak
Keyword(s):  
Heat Transfer ◽  
Phase Transformations ◽  
Steel Plate ◽  
Navier Stokes ◽  
Continuous Heating ◽  
Heating Process ◽  
Navier Stokes Equation ◽  
Coupled Heat Transfer ◽  
Laser Head ◽  
Kinetics Of

This work concerns numerical modelling and computer simulations of temperature field and phase transformations during Yb:YAG laser heating of sheets made of S355 steel. The distribution of laser power emitted by Trumpf laser head D70 is used in the analysis. The heat source is modelled on the basis of interpolation algorithms using geostatistical kriging method. Coupled heat transfer and fluid flow in the fusion zone are described respectively by transient heat transfer equation with convective term and Navier-Stokes equation. The kinetics of phase transformations and volumetric fractions of arising phases are obtained on the basis of Johnson-Mehl-Avrami (JMA) and Koistinen-Marburger (KM) models. Continuous Heating Transformation (CHT) diagram is used for heating process and Continuous Cooling Transformation (CCT) diagram is used for heated steel with the decomposition of final volume fractions of phases transformed form austenite dependant on cooling rates.

Sign in / Sign up

Export Citation Format

Share Document