Physical and Mechanical Properties of Two-Phase Zr-Cr-Mn Alloys

1998 ◽  
Vol 552 ◽  
Author(s):  
A. Goldberg ◽  
D. E. Luzzi

ABSTRACTThe Zr-Cr-Mn system is used to explore the effect of a lowered SFE on the room temperature mechanical properties of a Laves phase using elements of similar atomic size. The ternary Zr-Cr-Mn diagram in the region from 0 to 12 at. % Mn is first determined and it is shown that Mn substitutes only for Cr in the Laves phase. TEM analysis of the density of stacking fault energy related defects such as annealing twins indicates that Mn substitution for Cr in ZrCr2 lowers the SFE of the cubic Laves phase. Mechanical testing of the two phase alloys is used to explore the effects of Mn content and the volume fraction of each phase on the ductility and fracture behavior in compression. It is found that the mechanical properties are well-described by a model incorporating solid solution strengthening in a ductile-brittle two phase alloy.

2014 ◽  
Vol 1043 ◽  
pp. 17-21 ◽  
Author(s):  
Ravi Kant ◽  
Ashish Selokar ◽  
Vijaya Agarwala ◽  
U. Prakash

The effect of carbon addition on Fe-22.0Al-5.0Ti alloy on structure and properties has been investigated. Microstructural and phase analysis have been investigated by using optical microscopy, scanning electron microscope (SEM) equipped with EDAX. For low carbon addition (0.1 wt.%), two-phase microstructure consisting of precipitates of TiC in B2 matrix. The presence of large amount of carbon (1.0 or 1.5 wt.%) resulted formation of Fe3AlC0.5 and TiC precipitates in B2 matrix. The results show that the mechanical properties of Fe-22.0Al-5.0Ti increased with increase in the carbon content and strongly depend upon nature and volume fraction of different precipitates. The volume fraction of precipitates increased with increase in the content of carbon. The behavior of Fe-22.0Al-5.0Ti alloy was explained by the combined effect of precipitation hardening and solid solution strengthening. The main effect of addition of carbon related to improvement in the compressive strength without loss in the ductility. The decrease in the wear rate is mainly attributed to the high hardness of the composites and as well hard TiC play a role of load carrying.


2014 ◽  
Vol 783-786 ◽  
pp. 1195-1200 ◽  
Author(s):  
Katsushi Tanaka ◽  
Haruyuki Inui

The changes in the γ’ solvus temperature and the volume fraction of Co-Al-W based alloys with fcc / L12 two-phase microstructures upon alloying with quaternary elements have been investigated. All investigated quaternary elements, except for Fe and Re, increase the γ’ solvus temperatures of Co-Al-W based alloys with varying efficiencies depending on quaternary element. On the other hand, the variation of the γ’ volume fraction with alloying depends on the alloying element. Of the investigated quaternary elements, Ta is found to be the most effective in increasing the γ’ solvus temperature of Co-Al-W based alloys. The lattice mismatch significantly increase upon alloying with Ta of 4at.%, which destroys the coherent cuboidal structure.


2015 ◽  
Vol 1760 ◽  
Author(s):  
Daisuke Edatsugi ◽  
Yasuyuki Kaneno ◽  
Hiroshi Numakura ◽  
Takayuki Takasugi

ABSTRACTThe effect of W addition on microstructure and mechanical properties of Ni3Al (L12) and Ni3V (D022) two-phase intermetallic alloys has been investigated. W was added to the base alloy composition, Ni75Al10V12Nb3 (at. %) in place of either Ni, Al or V. The W-added alloy ingots were heat-treated in vacuum at 1575 K for 5 h. The majority of W-added alloys showed a dual two-phase microstructures while the alloy in which 3 at. % W substituted for Ni exhibited the dual two-phase microstructure containing W solid solution dispersions. Vickers hardness was significantly enhanced by W addition, which is primarily due to solid-solution strengthening.


Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 238
Author(s):  
Sujung Son ◽  
Jongun Moon ◽  
Hyeonseok Kwon ◽  
Peyman Asghari Rad ◽  
Hidemi Kato ◽  
...  

New AlxCo50−xCu50−xMnx (x = 2.5, 10, and 15 atomic %, at%) immiscible medium-entropy alloys (IMMEAs) were designed based on the cobalt-copper binary system. Aluminum, a strong B2 phase former, was added to enhance yield strength and ultimate tensile strength, while manganese was added for additional solid solution strengthening. In this work, the microstructural evolution and mechanical properties of the designed Al-Co-Cu-Mn system are examined. The alloys exhibit phase separation into dual face-centered cubic (FCC) phases due to the miscibility gap of the cobalt-copper binary system with the formation of CoAl-rich B2 phases. The hard B2 phases significantly contribute to the strength of the alloys, whereas the dual FCC phases contribute to elongation mitigating brittle fracture. Consequently, analysis of the Al-Co-Cu-Mn B2-strengthened IMMEAs suggest that the new alloy design methodology results in a good combination of strength and ductility.


Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1677
Author(s):  
Hooi Peng Lim ◽  
Willey Yun Hsien Liew ◽  
Gan Jet Hong Melvin ◽  
Zhong-Tao Jiang

This paper reviews the phase structures and oxidation kinetics of complex Ti-Al alloys at oxidation temperatures in the range of 600–1000 °C. The mass gain and parabolic rate constants of the alloys under isothermal exposure at 100 h (or equivalent to cyclic exposure for 300 cycles) is compared. Of the alloying elements investigated, Si appeared to be the most effective in improving the oxidation resistance of Ti-Al alloys at high temperatures. The effect of alloying elements on the mechanical properties of Ti-Al alloys is also discussed. Significant improvement of the mechanical properties of Ti-Al alloys by element additions has been observed through the formation of new phases, grain refinement, and solid solution strengthening.


2015 ◽  
Vol 817 ◽  
pp. 307-311 ◽  
Author(s):  
Peng Chao Zhang ◽  
Jin Chuan Jie ◽  
Yuan Gao ◽  
Tong Min Wang ◽  
Ting Ju Li

The Cu-Cr and Cu-Cr-Ti alloy plates were prepared by vacuum melting and plastic deformation. The effect of slight Ti element on microstructure and mechanical properties of Cu-Cr alloy was discussed. The result shows that Cr particles with spherical shape precipitated from Cu matrix after aging. Plenty Ti atoms dissolved in the vicinity of Cr particles and there were still parts of solid solution Ti atoms in other regions. Improvements in peak hardness and softening resistance were achieved with the addition of Ti element in Cu-Cr alloy. The addition of 0.1 wt.% Ti element makes Cu-Cr alloy possess tensile strength of 565 MPa and hardness of 185.9 HV after aging at 450 °C for 120 min, which can be attributed to multiple strengthening mechanisms, i.e. work hardening, solid solution strengthening and precipitation strengthening.


Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1633 ◽  
Author(s):  
Yan Zhao ◽  
Lifeng Fan ◽  
Bin Lu

In order to develop a third-generation automobile steel with powerful strength and elongation, we propose a method through high temperature quenching and two-phase region reverse-phase transformation annealing to develop such steel with 0.13% C and 5.4% Mn. To investigate the microstructure evolution and mechanical properties of manganese steel, SEM, XRD and TEM are employed in our experiments. Experimental results indicate that the microstructure after quenching is mainly lath martensite microstructure with average of lath width at 0.5 μm. The components of the steel after along with reverse-phase transformation annealing are ultra-fine grain ferrite, lath martensite and different forms of austenite microstructure. When the temperature at 625 °C, the components of the steel mainly includes lath martensite microstructure and ultra-fine grain ferrite and the fraction of austenite volume is only 5.09%. When the annealing temperature of reverse-phase transformation increase into 650 °C and 675 °C, the austenite appears in the boundary of the ferritic grain boundary and the boundary of lath martensite as the forms of bulk and lath. The phenomenon appears in the bulk of austenite, and the size of is 0.22 μm, 0.3 μm. The fraction of austenite volume is 22.34% at 675 °C and decreases into 9.32% at 700 °C. The components of austenite mainly includes ultra-fine grained ferrite and lath martensite. Furthermore, the density of decreases significantly, and the width of martensite increases into 0.32 μm. In such experimental settings, quenching at 930 °C with 20 min and at 675 °C with 30 min reverse-phase transformation annealing, the austenite volume fraction raises up to 22.34%.


2020 ◽  
Vol 34 (25) ◽  
pp. 2050269
Author(s):  
Yuqi Mao ◽  
Yuehong Zheng ◽  
Yu Shi ◽  
Min Zhu ◽  
Saitejin ◽  
...  

In order to further expand the application scope of 2205 duplex stainless steel (DSS), its microstructure and mechanical properties require as much attention as its corrosion properties. In this study, 2205DSSs were prepared by aluminothermic reaction and the microstructures and mechanical behavior of the rolled alloys were analyzed. The micro-nanocrystals composite structure appears in the alloys after rough rolling with deformation of 40% at [Formula: see text]C followed by finishing rolling with deformation of 30%, 50% and 70% at [Formula: see text]C. With the increase of rolling deformation, the two-phase structure is gradually elongated, the average size of the two-phase grains is gradually increased, and some [Formula: see text] phase will change to [Formula: see text] phase, the volume fraction of [Formula: see text] phase is gradually increased, and the distribution of nanocrystals is gradually uniform. Meanwhile, the fracture mode of alloy is gradually changed from ductile fracture to brittle fracture. The strength and hardness of the alloy increase gradually.


Crystals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 641 ◽  
Author(s):  
Di Tie ◽  
Boyu Zhang ◽  
Lufei Yan ◽  
Renguo Guan ◽  
Zhaoshan Ji ◽  
...  

The solidification and tensile deformation behaviors of rheo-cast AZ91-Sn alloys were revealed to study the effects of Sn alloying on improvement of AZ91 alloy’s mechanical properties. Two kinds of Mg17Al12 phases precipitated from the supersaturated magnesium matrix during rheo-solidification were observed: coarse discontinuous precipitates (DP) at grain boundaries and small-sized continuous precipitates (CP) inside grains. With increasing Sn content, the amount of Mg17Al12 phases was increased whilst the amount of Al atoms in the matrix was decreased. Due to the higher melting point of Mg2Sn than Mg17Al12, Mg2Sn precipitated earlier from the melt, and therefore provided heterogeneous nuclei for Mg17Al12 during the eutectic reaction. Due to grain refinement and solid solution strengthening, AZ91-2.4Sn (mass%) gained 52% increase in tensile strength and 93% increase in elongation compared with pure AZ91 alloy. The higher-density twins and microcracks induced by Sn alloying relaxed stress concentration during plastic deformation, so the fracture mode was transformed from cleavage fracture of pure AZ91 alloy to ductile fracture of AZ91-Sn alloys.


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