Phase Transformations in Metallic Materials

A special issue of Metals (ISSN 2075-4701).

Deadline for manuscript submissions: closed (20 July 2020) | Viewed by 20906

Special Issue Editor

Special Issue Information

Dear Colleagues,

Several metallic materials experience phase transformations during thermo/mechanical treatments, or when in service. These phase transformations can have a reversible or irreversible character and each lead to different properties. Therefore, fundamental understanding of the phase transformation characteristics and mechanisms in advanced materials is a topic of extreme relevance nowadays.

With this Special Issue, we invite contributions in the form of original research articles or reviews that address or elucidated on any type of phase transformation in metallic alloys systems. The scope of this Special Issue is not only limited to fundamental research and also welcomes works concerning any application where phase transformations are somehow involved.

Prof. João Pedro Oliveira
Guest Editor

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Keywords

  • Phase transformations
  • Microstructure
  • Characterization
  • Mechanical properties
  • Simulation

Published Papers (6 papers)

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Research

8 pages, 1815 KiB  
Article
Strain Rate Dependence of Hardness for PE and SME TiNi Alloys
by Lingyan Shen, Mengmeng Hui and Yonggui Liu
Metals 2020, 10(9), 1157; https://doi.org/10.3390/met10091157 - 27 Aug 2020
Cited by 2 | Viewed by 1884
Abstract
In this paper, the strain rate dependence of hardening behavior of polycrystalline pseudoelastic (PE) and shape memory effect (SME) TiNi alloy under impact loading was investigated by experiments. Measurements of stress–strain curves, hardening modulus, hysteresis loop area, and temperature variation are synchronized using [...] Read more.
In this paper, the strain rate dependence of hardening behavior of polycrystalline pseudoelastic (PE) and shape memory effect (SME) TiNi alloy under impact loading was investigated by experiments. Measurements of stress–strain curves, hardening modulus, hysteresis loop area, and temperature variation are synchronized using in situ infrared detector system at the strain rate range from 300/s to 2000/s. It is shown that with the strain rate increasing, for PE specimens, strain rate hardening is observed, while SME specimens perform a strong nonlinear strain hardening. The results of synchronous temperature measurement show that in stress-temperature space, for PE samples, the dynamic transformation path is strain rate independent, but for the SME samples, the opposite is true. Thermal-mechanical coupling does not seem to explain this difference, and hardening from microstructure variation should be considered for such difference. Full article
(This article belongs to the Special Issue Phase Transformations in Metallic Materials)
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17 pages, 10934 KiB  
Article
Studies on the β → α Phase Transition Kinetics of Ti–3.5Al–5Mo–4V Alloy under Isothermal Conditions by X-ray Diffraction
by Panpan Ge, Song Xiang, Yuanbiao Tan and Xuanming Ji
Metals 2020, 10(1), 90; https://doi.org/10.3390/met10010090 - 04 Jan 2020
Cited by 8 | Viewed by 3267
Abstract
The β → α phase transition kinetics of the Ti–3.5Al–5Mo–4V alloy with two different grain sizes was investigated at the isothermal temperature of 500 °C. A method to estimate the function of the precipitate fraction of the α phase with different aging times [...] Read more.
The β → α phase transition kinetics of the Ti–3.5Al–5Mo–4V alloy with two different grain sizes was investigated at the isothermal temperature of 500 °C. A method to estimate the function of the precipitate fraction of the α phase with different aging times was developed based on X-ray diffraction analysis. The value of the α precipitate fraction increased sharply at first, then increased slowly with the aging time, and finally reached equilibrium. The value of the α precipitate fraction was higher in the alloy aged for the same time at a higher solution temperature, while the size of the α precipitate was smaller at a higher solution temperature. The β → α phase transition kinetics under isothermal conditions were modeled in the theoretical frame of the Johnson–Mehl–Avrami–Kolmogorov (JMAK) theory. The kinetic parameters of JMAK deduced different transformation mechanisms. The mechanism of the phase transition in the first stage was dominated by mixed transformation mechanisms (homogeneously nucleated and acicular-grown α structure, and grain boundary-nucleated and grown α precipitate), while the second stage was the growth of the fine α precipitate, which was controlled by slow diffusion. As the aging time increased, the hardness of the Ti–3.5Al–5Mo–4V alloy increased sharply. After the hardness of the alloy reached a plateau, it began to decline. The hardness of the alloy was always higher at a higher solution temperature. Full article
(This article belongs to the Special Issue Phase Transformations in Metallic Materials)
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8 pages, 2288 KiB  
Communication
Low-Temperature Induced Martensitic Transformation Enhancing Mechanical Properties of Metastable Fe-Ni-P Alloy
by Guodong Cui, Runjian Jiang, Chengsong Zhang and Yuxuan Liu
Metals 2019, 9(7), 785; https://doi.org/10.3390/met9070785 - 14 Jul 2019
Cited by 1 | Viewed by 2795
Abstract
The metastable Fe-Ni-P alloy with phosphorus (P) solid-solution structure has been fabricated by spark plasma sintering. Its face-centered cubic (FCC) matrix without the precipitation of phosphide attains a high plasticity and an excellent strain hardening ability at room temperature. This Fe-Ni-P alloy is [...] Read more.
The metastable Fe-Ni-P alloy with phosphorus (P) solid-solution structure has been fabricated by spark plasma sintering. Its face-centered cubic (FCC) matrix without the precipitation of phosphide attains a high plasticity and an excellent strain hardening ability at room temperature. This Fe-Ni-P alloy is subjected to cryogenic treatment at various temperatures (−20 °C and −50 °C), to investigate the role of phosphorus on the microstructural evolution and mechanical properties of γ-(Fe-Ni) alloy at low temperatures. The results indicate that the addition of phosphorus can destabilize the Fe-Ni-P alloy and facilitate its martensitic transformation during cryogenic treatment. P-doping does not lead to obvious embrittlement of Fe-Ni-P alloy at low temperatures, but strengthens the alloy by promoting microstructure evolution. The Fe-Ni-P alloy has high plasticity and good strain hardening ability after treated at −20 °C, and is converted to acicular martensite structure after being treated at −50 °C, resulting in a significant increase in its hardness (433 HV) and compressive yield strength (1271 MPa). Developing this Fe-Ni-P alloy as a load-bearing component for low-temperature conditions shows great promise. Full article
(This article belongs to the Special Issue Phase Transformations in Metallic Materials)
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11 pages, 4228 KiB  
Article
Optimization of Induction Quenching Processes for HSS Roll Based on MMPT Model
by Ligang Liu, Hui Yu, Zhiqiang Yang , Chunmei Zhao and Tongguang Zhai
Metals 2019, 9(6), 663; https://doi.org/10.3390/met9060663 - 06 Jun 2019
Cited by 2 | Viewed by 2988
Abstract
To improve the comprehensive performance of high speed steel (HSS) cold rolls, the induction hardening processes were analyzed by numerical simulation and experimental research. Firstly, a modified martensitic phase transformation (MMPT) model of the tested steel under stress constraints was established. Then, the [...] Read more.
To improve the comprehensive performance of high speed steel (HSS) cold rolls, the induction hardening processes were analyzed by numerical simulation and experimental research. Firstly, a modified martensitic phase transformation (MMPT) model of the tested steel under stress constraints was established. Then, the MMPT model was fed into DEFORM to simulate the induction quenching processes of working rolls based on an orthogonal test design and the optimal dual frequency of the induction quenching process was obtained. The results indicate that the depth of the roll’s hardened layer increases by 32.5% and the axial residual tensile stress also becomes acceptable under the optimized process. This study provides guidance for studying phase transformation laws under stress constraints and the optimization of complex processes in an efficient manner. Full article
(This article belongs to the Special Issue Phase Transformations in Metallic Materials)
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14 pages, 10611 KiB  
Article
Microstructure Evolution during the Production of Dual Phase and Transformation Induced Plasticity Steels Using Modified Strip Casting Simulated in the Laboratory
by Zhiping Xiong, Andrii G. Kostryzhev, Yanjun Zhao and Elena V. Pereloma
Metals 2019, 9(4), 449; https://doi.org/10.3390/met9040449 - 16 Apr 2019
Cited by 10 | Viewed by 3826
Abstract
Instead of conventional steel making and continuous casting followed by hot and cold rolling, strip casting technology modified with the addition of a continuous annealing stage (namely, modified strip casting) is a promising short-route for producing ferrite-martensite dual-phase (DP) and multi-phase transformation-induced plasticity [...] Read more.
Instead of conventional steel making and continuous casting followed by hot and cold rolling, strip casting technology modified with the addition of a continuous annealing stage (namely, modified strip casting) is a promising short-route for producing ferrite-martensite dual-phase (DP) and multi-phase transformation-induced plasticity (TRIP) steels. However, at present, the multi-phase steels are not manufactured by the modified strip casting, due to insufficient knowledge about phase transformations occurring during in-line heat treatment. This study analysed the phase transformations, particularly the formation of ferrite, bainite and martensite and the retention of austenite, in one 0.17C-1.52Si-1.61Mn-0.195Cr (wt. %) steel subjected to the modified strip casting simulated in the laboratory. Through the adjustment of temperature and holding time, the characteristic microstructures for DP and TRIP steels have been obtained. The DP steel showed comparable tensile properties with industrial DP 590 and the TRIP steel had a lower strength but a higher ductility than those industrially produced TRIP steels. The strength could be further enhanced by the application of deformation and/or the addition of alloying elements. This study indicates that the modified strip casting technology is a promising new route to produce steels with multi-phase microstructures in the future. Full article
(This article belongs to the Special Issue Phase Transformations in Metallic Materials)
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24 pages, 7374 KiB  
Article
Grain Boundary Complexions and Phase Transformations in Al- and Cu-Based Alloys
by Olga Kogtenkova, Boris Straumal, Anna Korneva, Tomasz Czeppe, Anna Wierzbicka-Miernik, Marek Faryna and Pawel Zięba
Metals 2019, 9(1), 10; https://doi.org/10.3390/met9010010 - 21 Dec 2018
Cited by 9 | Viewed by 4841
Abstract
High-pressure torsion has been used to obtain the ultra-fine grained (UFG) state with a high specific area of grain boundaries (GBs) in Al-Zn, Al-Mg, Cu-Ag, Cu-Co, and Cu-Ni solid solutions with face-centered cubic (fcc) lattices. The UFG samples were heated in a differential [...] Read more.
High-pressure torsion has been used to obtain the ultra-fine grained (UFG) state with a high specific area of grain boundaries (GBs) in Al-Zn, Al-Mg, Cu-Ag, Cu-Co, and Cu-Ni solid solutions with face-centered cubic (fcc) lattices. The UFG samples were heated in a differential scanning calorimeter (DSC). Small endothermic peaks in the DSC curves were observed in the one-phase solid-solution area of the respective phase diagrams, i.e., far away from the bulk solidus and solvus lines. A possible explanation of these endothermic peaks is based on the hypothesis of phase transformations between GB complexions. This hypothesis has been supported by observations with transmission electron microscopy and electron backscattering diffraction. The new lines of GB phase transformations have been constructed in the Al-Zn, Al-Mg, Cu-Ag, Cu-Co, and Cu-Ni bulk phase diagrams. Full article
(This article belongs to the Special Issue Phase Transformations in Metallic Materials)
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