Spinodal decomposition and martensitic transformation of the high manganese Mn‒xCu alloys fabricated by additive manufacturing

2021 ◽  
Vol 25 ◽  
pp. 101170
Author(s):  
Jingjing Yang ◽  
Chunyang Zhao ◽  
Hailong Liang ◽  
Zemin Wang ◽  
Chenyu Su
Keyword(s):  
Additive Manufacturing ◽  
Martensitic Transformation ◽  
Spinodal Decomposition ◽  
High Manganese

scholarly journals Significantly fast spinodal decomposition and inhomogeneous nanoscale martensitic transformation in Ti–Nb–O alloys

2020 ◽  
Vol 321 ◽  
pp. 11049
Author(s):  
Yuya ISHIGURO ◽  
Yuhki TSUKADA ◽  
Toshiyuki KOYAMA
Keyword(s):  
Heat Treatment ◽  
Martensitic Transformation ◽  
Spinodal Decomposition ◽  
Treatment Temperature ◽  
Phase Field Method ◽  
Isothermal Heat Treatment ◽  
Phase Decomposition ◽  
Rate Condition ◽  
Continuous Cooling ◽  
Β Phase

The β phase spinodal decomposition during continuous cooling in Ti‒Nb‒O alloys is investigated by the phase-field method. Addition of only a few at.%O to Ti‒23Nb (at.%) alloy remarkably increases the driving force of the β phase spinodal decomposition. During isothermal heat treatment at 1000 K and 1100 K in Ti‒23Nb‒3O (at.%) alloy, the β phase separates into β1 phase denoted as (Ti)1(O, Va)3 and β2 phase denoted as (Ti, Nb)1(Va)3, resulting in the formation of nanoscale concentration modulation. The phase decomposition progresses in 0.3‒20 ms. In Ti‒23Nb‒XO alloys (X = 1.0, 1.2, 2.0), the spinodal decomposition occurs during continuous cooling with the rate of 500 K s‒1, indicating that the spinodal decomposition occurs during water quenching in the alloys. It is assumed that there is a threshold value of oxygen composition for inducing the spinodal decomposition because it does not occur during continuous cooling in Ti‒23Nb‒0.6O (at.%) alloy. The concentration modulation introduced by the β phase decomposition has significant effect on the β→α” martensitic transformation. Hence, it seems that for controlling microstructure and mechanical properties of Ti‒Nb‒O alloys, careful control of heat treatment temperature and cooling rate condition is required.

scholarly journals Wire Arc Additive Manufactured CuMn13Al7 High-Manganese Aluminium Bronze

2020 ◽  
Author(s):  
Chun Guo ◽  
Bai-Song Hu ◽  
Bao-Li Wei ◽  
Feng Chen
Keyword(s):  
Electron Microscope ◽  
Additive Manufacturing ◽  
Grain Boundary ◽  
Manufacturing Technology ◽  
High Manganese ◽  
Direct Reading ◽  
Metallographic Structure ◽  
Additive Manufacturing Technology ◽  
Aluminium Bronze ◽  
Equiaxed Grain

Abstract In this work, high-manganese aluminium bronze CuMn13Al7 samples were prepared by arc additive manufacturing technology. The phase composition, microstructure, and crystal structure of the high-manganese aluminium bronze CuMn13Al7 arc additive manufactured samples were analysed using direct-reading spectrometer, metallographic microscope, scanning electron microscope, and transmission electron microscope. The micro-hardness tester, tensile tester, impact tester, and electrochemical workstation were also used to test the performance of the CuMn13Al7 samples. By studying the microstructure and properties of the CuMn13Al7 samples, it was found that preparation of the samples by the arc additive manufacturing technology ensured good forming quality, almost no defects, and good metallurgical bonding inside the sample. The metallographic structure (α + β + point phase) mainly comprises the following: the metallographic structure in the equiaxed grain region has an obvious grain boundary α; the metallographic structure in the remelting region has no obvious grain boundary α; the thermal influence on the metallographic structure produced a weaker grain boundary α than the equiaxed grain region. The transverse and longitudinal cross sections of the sample had uniform microhardness distributions, and the average microhardness values were 190.5 HV0.1 and 192.7 HV0.1, respectively. The sample also had excellent mechanical properties: yield strength of 301 MPa, tensile strength of 633 MPa, elongation of 43.5%, reduction of area by ​​58%, Charpy impact value of 68 J at –20 ℃, and dynamic potential polarisation curve test results. Further, it was shown that the average corrosion potential of the sample was –284.5 mV, and the average corrosion current density was 4.1 × 10–3 mA/cm2.

Spinodal decomposition and martensitic transformation kinetics of the 82.2Mn-15.8Cu-2Al thermosensitive damping alloy

2020 ◽  
Vol 683 ◽  
pp. 178321 ◽  
Author(s):  
Cuizhen Deng ◽  
Wenyi Peng ◽  
Zhiqiang Xiong ◽  
Wen He ◽  
Yongcun Ma ◽  
...  
Keyword(s):  
Martensitic Transformation ◽  
Spinodal Decomposition ◽  
Transformation Kinetics ◽  
Kinetics Of

Impact and Rolling Abrasive Wear Behavior and Hardening Mechanism for Hot-Rolled Medium-Manganese Steel

2018 ◽  
Vol 140 (3) ◽  
Author(s):  
Jian Wang ◽  
Qingliang Wang ◽  
Xiao Zhang ◽  
Dekun Zhang
Keyword(s):  
Wear Resistance ◽  
Martensitic Transformation ◽  
Work Hardening ◽  
Wear Behavior ◽  
Manganese Steel ◽  
High Manganese ◽  
High Manganese Steel ◽  
Medium Manganese Steel ◽  
Dislocation Strengthening ◽  
Hot Rolled

The coupled impact and rolling wear behavior of the medium-manganese austenitic steel (Mn8) were studied by comparison with the traditional Hadfield (Mn13) steel. Scanning electron microscopy (SEM), X-ray diffractometer (XRD), and transmission electron microscope (TEM) were used to analyze the wear and hardening mechanisms. The experimental results show that the impact and rolling wear resistance of hot-rolled medium-manganese steel (Mn8) is better than that of high-manganese steel (Mn13) under conditions of low-impact load. The better work hardening sensitivity effectively improves the wear resistance of medium-manganese steel. Not only the coefficient of friction is low, but the mass loss and wear rate of the wear are lower than that of high-manganese steel. After impact and rolling wear, a hardened layer with a thickness of about 600 μm is formed on the wear surface. The highest microhardness of the subsurface layer for Mn8 is about 594 HV and the corresponding Rockwell hardness is about 55 HRC, showing the remarkable work hardening effect. The wear-resistant strengthening mechanism of medium-manganese steel is compound strengthening, including the deformation-induced martensitic transformation, dislocation strengthening, and twin strengthening. In initial stages of impact and rolling abrasion, dislocation strengthening plays a major role. When the deformation reaches a certain extent, the deformation-induced martensitic transformation and twinning strengthening begin to play a leading role.

scholarly journals Influence of annealing on the functional properties of the NiTi alloy produced by wire arc additive manufacturing

2022 ◽  
Vol 1213 (1) ◽  
pp. 012002
Author(s):  
N Resnina ◽  
I A Palani ◽  
S Belyaev ◽  
R Bikbaev ◽  
Shalini Singh ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Martensitic Transformation ◽  
Annealing Temperature ◽  
Volume Fraction ◽  
Niti Alloy ◽  
Strain Variation ◽  
Recoverable Strain ◽  
Niti Phase ◽  
Working Length ◽  
Wire Arc Additive Manufacturing

Abstract The influence of the annealing temperature on the recoverable strain variation on cooling and heating under a stress of 200 MPa was studied in the NiTi samples produced by wire arc additive manufacturing. The samples including the Ni-rich NiTi layer in the working length were annealed for 10 hours at various temperature from 450 to 600 °C. It is shown that an increase in annealing temperature leads to non-monontonic variation in the recoverable strain. This is caused by an increase in annealing temperature from 450 to 550 °C increases the volume fraction of Ni4Ti3 precipitates. As a result, the volume fraction of the NiTi phase undergoing the martensitic transformation and recoverable strain decrease. An increase in annealing temperature from 550 to 600 °C leads to a dissolving the Ni4Ti3 precipitates and formation of the Ni3Ti2 precipitates that increases the volume fraction of the NiTi phase and the recoverable strain.

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