scholarly journals Effect of Strain on Transformation Diagrams of 100Cr6 Steel

Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 326 ◽  
Author(s):  
Rostislav Kawulok ◽  
Ivo Schindler ◽  
Jaroslav Sojka ◽  
Petr Kawulok ◽  
Petr Opěla ◽  
...  
Keyword(s):  
Cooling Rate ◽  
Uniaxial Compression ◽  
Martensite Formation ◽  
Cooling Rates ◽  
Critical Cooling Rate ◽  
Transformation Diagrams ◽  
Kinetics Of

Based on dilatometric tests, the effect of various values of previous deformation on the kinetics of austenite transformations during the cooling of 100Cr6 steel has been studied. Dilatometric tests have been performed with the use of the optical dilatometric module of the plastometer Gleeble 3800. The obtained results were compared to metallographic analyses and hardness measurements HV30. Uniaxial compression deformations were chosen as follows: 0, 0.35, and 1; note that these are true (logarithmic) deformations. The highly important finding was the absence of bainite. In addition, it has been verified that with the increasing amount of deformation, there is a further shift in the pearlitic region to higher cooling rates. The previous deformation also affected the temperature martensite start, which decreased due to deformation. The deformation value of 1 also shifted the critical cooling rate required for martensite formation from the 12 °C/s to 25 °C/s.

scholarly journals Development of Precipitation Hardening Parameters for High Strength Alloy AA 7068

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 918
Author(s):  
Julia Osten ◽  
Benjamin Milkereit ◽  
Michael Reich ◽  
Bin Yang ◽  
Armin Springer ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Cooling Rate ◽  
Maximum Yield ◽  
High Strength ◽  
Tensile Tests ◽  
Age Hardening ◽  
Scanning Calorimetry ◽  
Cooling Rates ◽  
Critical Cooling Rate ◽  
Kinetics Of

The mechanical properties after age hardening heat treatment and the kinetics of related phase transformations of high strength AlZnMgCu alloy AA 7068 were investigated. The experimental work includes differential scanning calorimetry (DSC), differential fast scanning calorimetry (DFSC), sophisticated differential dilatometry (DIL), scanning electron microscopy (SEM), as well as hardness and tensile tests. For the kinetic analysis of quench induced precipitation by dilatometry new metrological methods and evaluation procedures were established. Using DSC, dissolution behaviour during heating to solution annealing temperature was investigated. These experiments allowed for identification of the appropriate temperature and duration for the solution heat treatment. Continuous cooling experiments in DSC, DFSC, and DIL determined the kinetics of quench induced precipitation. DSC and DIL revealed several overlapping precipitation reactions. The critical cooling rate for a complete supersaturation of the solid solution has been identified to be 600 to 800 K/s. At slightly subcritical cooling rates quench induced precipitation results in a direct hardening effect resulting in a technological critical cooling rate of about 100 K/s, i.e., the hardness after ageing reaches a saturation level for cooling rates faster than 100 K/s. Maximum yield strength of above 600 MPa and tensile strength of up to 650 MPa were attained.

Effects of RE on Critical Cooling Rate of Bearing-B Steel

2012 ◽  
Vol 535-537 ◽  
pp. 761-763 ◽  
Author(s):  
Yi Sheng Zhao ◽  
Xin Ming Zhang ◽  
Zhi Guo Gao
Keyword(s):  
Phase Change ◽  
Cooling Rate ◽  
Experimental Results ◽  
Cooling Rates ◽  
Critical Cooling Rate ◽  
The Law

The law of phase change of bearing-B steel during continual cooling was studied by adopting dilatometer. The CCT curves of bearing-B steel were drawn, and the effects of RE on critical cooling rates were studied. The experimental results show that the start temperatures of martensite TM was decreased from 438 to 404°C. The critical cooling rate was simultaneously decreased from 33 to 15°C/s.

Experimental petrology, Reconstruction of rock cooling paths from kinetic data on the Fe 2 +—Mg exchange reaction in anthophyllite

1977 ◽  
Vol 286 (1336) ◽  
pp. 303-311 ◽  
Keyword(s):  
Simple Model ◽  
Exchange Reaction ◽  
Kinetic Data ◽  
Experimental Petrology ◽  
Cooling Rates ◽  
Temperature Transformation ◽  
Transformation Diagrams ◽  
Kinetics Of

The kinetics of the intracrystalline Fe-Mg exchange reaction in anthophyllite can be described by a simple model that permits extrapolation to lower temperatures. Rock cooling rates can be estimated in the vicinity of 300 °C from these data using time-temperature-transformation diagrams. Aluminous orthoamphiboles (gedrites) are expected to yield rock cooling rates at higher temperatures.

Solidification Modeling of Bulk Amorphous Alloys

2003 ◽  
Vol 806 ◽  
Author(s):  
Sang Bok Lee ◽  
Nack J. Kim
Keyword(s):  
Heterogeneous Nucleation ◽  
Amorphous Alloys ◽  
Nucleation Theory ◽  
Cooling Rates ◽  
Continuous Cooling ◽  
Wide Range ◽  
Temperature Transformation ◽  
Transformation Diagrams ◽  
Experimental Values ◽  
Kinetics Of

ABSTRACTClassical heterogeneous nucleation theory coupled with DTA data has been used to closely estimate the crystallization behavior of continuously cooled bulk metallic glass (BMG) alloys. Continuous cooling transformation and time temperature transformation diagrams of three BMG alloys, Zr41.2Ti13.8Cu12.5Ni10Be22.5, Cu47Ti33Zr11Ni6Si1Sn2 and Mg65Cu25Y10 alloys, have been calculated. The critical cooling rates Rc of three alloys were calculated to be 1.7 K/s, 242 K/s and 36 K/s for Zr41.2Ti13.8Cu12.5Ni10Be22.5, Cu47Ti33Zr11Ni6Si1Sn2 and of Mg65Cu25Y10 alloys, respectively, which match well with the experimental values. We conclude that heterogeneous nucleation is more favorable than homogeneous nucleation for the formation of crystals during cooling of BMG alloy liquids. Our approach can be applied to the analyses of crystallization kinetics of BMG alloys with a wide range of critical cooling rates during continuous cooling as well as isothermal annealing.

scholarly journals Continuous Cooling Transformation of Under-Cooled Austenite of SXQ500/550DZ35 Hydropower Steel

Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1562
Author(s):  
Zhenglei Tang ◽  
Ran Guo ◽  
Yang Zhang ◽  
Zhen Liu ◽  
Yuezhang Lu ◽  
...  
Keyword(s):  
Cooling Rate ◽  
Hardness Measurement ◽  
Cooling Rates ◽  
Continuous Cooling Transformation ◽  
Continuous Cooling ◽  
Continuous Cooling Transformation Diagrams ◽  
Transformation Diagrams ◽  
Hot Rolled ◽  
Vickers Hardness Measurement ◽  
Undercooled Austenite

The expansion curves of the continuous cooling transformation of undercooled austenite of SXQ500/550DZ35 hydropower steel at different heating temperatures and cooling rates were measured by use of a DIL805A dilatometer. Combined with metallography and Vickers hardness measurement, the continuous cooling transformation diagrams (CCT) of the studied steel under two different states were determined. The results show that in the first group of tests, after the hot-rolled specimens were austenitized at 920 °C, when the cooling rate was below 1 °C·s−1, the microstructure was composed of ferrite (F), pearlite (P) and bainite (B). With the cooling rates between 1 °C·s−1 and 5 °C·s−1, the microstructure was mainly bainite, and martensite (M) formed as the cooling rate reached 5 °C·s−1. When the cooling rate was up to 10 °C·s−1, the microstructure was completely martensite and the hardness value increased significantly. In the second group of tests, after the hot-rolled specimens were quenched at 920 °C and then heated at an intercritical temperature of 830 °C, in comparison with the first group of tests, and except for additional undissolved ferrites in each cooling rate range, the other microstructure types were basically the same. Due to the existence of undissolved ferrite, the microstructures of the specimens heated at intercritical temperatures were much finer, and the toughness values at low temperatures were better.

Kinetics and Mechanisms of Formation of Al-Ni Intermetallics

1986 ◽  
Vol 81 ◽  
Author(s):  
J. A. Patchett ◽  
G. J. Abbaschian
Keyword(s):  
Cooling Rate ◽  
Nucleation And Growth ◽  
Primary Phase ◽  
Peritectic Temperature ◽  
Cooling Rates ◽  
Fault Density ◽  
Metastable Extension ◽  
Mechanisms Of Formation ◽  
Free Growth ◽  
Kinetics Of

AbstractThe effects of cooling rate and composition on the nucleation and growth kinetics of NiAl, Ni2Al3, and NiAl3 intermetallics were studied for alloys containing 25 and 31.5 ht.% Ni. Fgr the former composition, the peritectic regction Ni Al + Liquid → NiAl3 was studied over cooling rates from 20 to 105 K/s. For the latter composhtion, the reaction NiAl + Liquid → Ni2Al3 was studied at cooling rates ranging form 10 to 600 K/sec. The amounis of constituent phases are shown to depend on the cooling rate, and for the peritectic phases, on the surface area of the primary phase. The nucleation of Ni2Al3 and NiAl3, and the ordering of the aluminum-rich NiAl were also examines uding trans ission electron microscopy. Cooling the NiAl + liquid below the peritectic temperature results in a metastable extension of NiAl with a high dislocation and stacking fault density, followed by the epitaxial nucleation and almost dislocation-free growth of Ni2Al3 In contrast, the nucleation of the NiAl3 on Ni2Al3 occurs directly witgoud the formationof an intermediate region.

Phase transformations in Ti3Al and Ti3Al + Mo aluminides

1991 ◽  
Vol 6 (5) ◽  
pp. 969-986 ◽  
Author(s):  
S. Djanarthany ◽  
C. Servant ◽  
R. Penelle
Keyword(s):  
Phase Transformations ◽  
Cooling Rate ◽  
Titanium Aluminides ◽  
Cooling Rates ◽  
Continuous Cooling Transformation ◽  
Continuous Cooling ◽  
Continuous Cooling Transformation Diagrams ◽  
Transformation Diagrams ◽  
Phase Relationships

We have analyzed the phase relationships in two titanium aluminides containing 3.4 at. % Mo with different aluminum compositions. The alloys were first homogenized in the β field, then cooled continuously at different cooling rates from 80 °C/s to 0.1 °C/s. The continuous cooling transformation diagrams (CCT) show that phase transformations and resulting microstructures are highly dependent on cooling rate. The microstructure consists of ordered α2 (DO19), ordered β0 (B2), and athermal ω (hexagonal) phases. The “tweed microstructure” is observed. The evolution of microhardness was determined as well as the relative partitioning of Al and Mo in (α2', α2) and β0 phases as a function of cooling rate.

Method for Estimating the Critical Cooling Rate for Glass Formation from Isothermal TTT Data

2007 ◽  
Vol 336-338 ◽  
pp. 1874-1877 ◽  
Author(s):  
Dong Mei Zhu ◽  
Wan Cheng Zhou ◽  
Chandra S. Ray ◽  
Delbert E. Day
Keyword(s):  
Cooling Rate ◽  
Glass Formation ◽  
Lithium Disilicate ◽  
Nucleating Agent ◽  
Cooling Rates ◽  
Continuous Cooling Transformation ◽  
Critical Cooling Rate ◽  
Continuous Cooling ◽  
Transformation Curve ◽  
Continuous Cooling Transformation Curve

A method is proposed for estimating the critical cooling rate for glass formation and continuous cooling transformation curve (CCT) from isothermal TTT data. The critical cooling rates and CCT curves for a group of lithium disilicate glasses containing different amount of Pt as nucleating agent estimated through this method are compared with the experimentally measured values and it shows this method can give a reasonable estimation.

Effect of Hot Deformation and Cooling Rate on Phase Transformations in Low Carbon HN5MVNb Bainitic Steel

2007 ◽  
Vol 539-543 ◽  
pp. 4620-4625 ◽  
Author(s):  
Andrzej Kazimierz Lis ◽  
Jadwiga Lis
Keyword(s):  
Cooling Rate ◽  
Local Equilibrium ◽  
Bainitic Steel ◽  
Low Carbon ◽  
Transformation Mechanism ◽  
Bainite Transformation ◽  
Equilibrium Conditions ◽  
Cooling Rates ◽  
Kinetics Of ◽  
Transformation Processes

Deformations at temperatures 900 °C, 860 °C, 810 °C and 780 °C in the consecutive amounts 24%, 20%, 19% and 18.5% were applied to low carbon HN5MVNb bainitic steel using hot compression testing in dilatometer Bähr 805 followed by continuous cooling. The results show clearly that the kinetics of the austenite decomposition were depended on local equilibrium conditions between recovery, recrystallization and phase transformation processes for a given cooling rate. Bainite transformation was accelerated when sample was cooled after deformation at cooling rate 60 °C/s. At lower cooling rates than 5 °C/s down to 0.5 °C/s, bainite transformation was postpone when comparing its kinetics with those for non deformed steel. The bainitic transformation cannot be fitted to a single transformation mechanism owing to the formation of carbides. Different behavior was observed for austenite to ferrite transformation. Usually it was accelerated with consecutive deformations of the steel for all cooling rates used in experiments.

Critical Cooling Rate for the Glass Formation of Fe80-XCoxP13C7 Alloy

2013 ◽  
Vol 745-746 ◽  
pp. 799-808
Author(s):  
Kai Xu ◽  
Yan Wang ◽  
Qiang Li
Keyword(s):  
Amorphous Alloy ◽  
Cooling Rate ◽  
Thermodynamic Data ◽  
Glass Formation ◽  
Amorphous Alloys ◽  
Experimental Results ◽  
Bulk Amorphous Alloy ◽  
Cooling Rates ◽  
Critical Cooling Rate ◽  
Dta Curves

In this work, the critical cooling rate Rc for glass formation of a series of Fe80-xCoxP13C7 (x = 0, 5, 10, 15, 20 at.%) alloys was determined by means of constructing CCT curves using Uhlmanns method. The calculated critical cooling rates for x = 0, 5, 10, 15, 20 at.% are 621, 441, 548, 894, 922 K/s, respectively. These results well coincide with the maximum diameters of Fe80-xCoxP13C7 amorphous alloys determined by experiments varying with the content of Co. The calculated Rc was also on the reasonable order of magnitudes. In addition, the values of three common GFA criterions of Trg, ΔTx and γ were calculated according to the thermodynamic data determined from DSC and DTA curves of Fe80-xCoxP13C7 (x = 0, 5, 10, 15, 20 at.%) bulk amorphous alloy. The validity of these GFA criterions in the series of Fe80-xCoxP13C7 (x = 0, 5, 10, 15, 20 at.%) alloys were investigated and it was pointed out that these three GFA criterions were not able to explain the experimental results of the maximum diameters of Fe80-xCoxP13C7 amorphous alloys varying with the content x of Co.

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