Mechanical Properties of Zr-Added Fe-Al Intermetallic Alloys Containing Large Second Phase Particles

2007 ◽  
Vol 561-565 ◽  
pp. 399-402 ◽  
Author(s):  
J. Machida ◽  
Satoru Kobayashi ◽  
Yasuyuki Kaneno ◽  
Takayuki Takasugi

Mechanical properties of thermomechanically fabricated D03 Fe-33Al and B2 Fe-38Al intermetallic alloys containing Zr were investigated by means of tensile test and microhardness measurement. The Zr-added ternary alloys showed fine-grained microstructure containing large (Fe,Al)12Zr τ1 phase particles, while the binary alloy showed a single-phase microstructure consisted of coarse recrystallized grains. By introducing the large τ1 phase particles to Fe-Al matrix, tensile strength at room temperature as well as at high temperature (873K) was enhanced but tensile ductility at both temperatures decreased. On the other hand, it was found that vacancy hardening which was significant in the alloys with high contents of Al (i.e., Fe-38Al) was reduced by the large τ1 phase particles.

Author(s):  
Ivan E. Locci ◽  
P. S. Khadkikar ◽  
R. D. Noebe ◽  
K. Vedula

An overwhelming amount of research has been performed on Ni3Al (γ’) and NiAl (β) intermetallic alloys over the last decade. Yet, very little is known about the two phase field between these ordered compounds, including the occurrence and stability of phases other than γ’ or β Identifying and understanding these other phases are important since one approach to improving the ductility and toughness of NiAl is to design an alloy with a dual phase microstructure (i.e. NiAl + Ni3Al). Preliminary alloying attempts have encountered varying degrees of success. They range from powder metallurgy alloys with significantly increased fracture strengths over single phase (β-alloys to directionally solidified γ’ + β crystals which exhibit up to 9% tensile ductility at room temperature. Unfortunately, aging of these alloys at low temperature (<973 K) results in the formation of several complex, stable and metastable phases which may negate any original improvements in mechanical behavior.


2017 ◽  
Vol 36 (2) ◽  
pp. 167-173 ◽  
Author(s):  
Chaopeng Cui ◽  
Yimin Gao ◽  
Shizhong Wei ◽  
Guoshang Zhang ◽  
Yucheng Zhou ◽  
...  

AbstractMo-0.5Ti and Mo-0.1Zr alloys were prepared by powder metallurgy. In Mo-0.5Ti and Mo-0.1Zr alloys, there appears the second-phase particles of Ti2O3 and ZrO2 respectively, each of which can effectively prevent the dislocation activity in the process of plastic deformation. The addition of Zr can increase the strength of molybdenum alloys. Meanwhile, the ZrO2 formed from the alloy element Zr can refine the grains of molybdenum alloys to improve the recrystallization plasticity. After annealing, the tensile strength decreases while the plasticity greatly increases compared to the annealed Mo-0.5Ti and Mo-0.1Zr alloys. With the increase of annealing temperature, both the tensile strength and plasticity of Mo-0.5Ti and Mo-0.1Zr alloys decrease. Compared with pure Mo, after annealing the properties of the Mo-0.5Ti alloy and the plasticity of the Mo-0.1Zr alloy significantly increases.


2006 ◽  
Vol 980 ◽  
Author(s):  
Yasuyuki Kaneno ◽  
Takayuki Takasugi ◽  
Mitsuhiko Yoshida ◽  
Hiroshi Tsuda

AbstractB2 (CsCl) CoZr intermetallic alloys with different chemical compositions were hot-rolled and subsequently recrystallized to evaluate tensile properties and rolling workability. Co-49.0Zr, -49.5Zr and -50.0Zr alloys showed the B2-matrixed microstructure containing C15 Co2Zr dispersions, while Co-50.5Zr and -51.0Zr alloys showed the B2-matrixed microstructure containing C16 CoZr2 dispersions. These homogenized ingots were successfully hot-rolled without edge cracks, except for the Co-51.0Zr alloy. The tensile tests revealed that the Co-49.5Zr, -50.0Zr and -50.5Zr alloys exhibited a notable tensile ductility at room temperature as well as at elevated temperatures. Moreover, the recrystallized CoZr alloys were cold-rolled up to 70% reduction without intermediate annealing. It was also found that tensile ductility was most prominent in the Co-50.0Zr alloy with the least volume fraction of second phase dispersions in the investigated alloys, suggesting that the B2 phase of CoZr was inherently ductile. Deformation microstructures were characterized by means of XRD and TEM observations. Mechanisms responsible for the observed large tensile ductility of the CoZr alloys were discussed, on the basis of the observed deformation microstructures.


2014 ◽  
Vol 58 ◽  
pp. 535-542 ◽  
Author(s):  
P. Shaterani ◽  
A. Zarei-Hanzaki ◽  
S.M. Fatemi-Varzaneh ◽  
S.B. Hassas-Irani

2012 ◽  
Vol 715-716 ◽  
pp. 286-291
Author(s):  
Sivaswamy Giribaskar ◽  
Gouthama ◽  
Rajesh Prasad

Development of bulk ultra-fine grained (UFG) materials by severe plastic deformation to attain improved mechanical properties is becoming more attractive and extensively studied nowadays. Equal channel angular extrusion (ECAE) is one of technique used effectively for obtaining bulk UFG materials. Novelty of this technique is one can build up significant amount of plastic strain by increasing the number of passes without much dimensional change. In present investigation dynamic recrystallization at deformation zones around the non-shearable second phase particles in Al-Li based alloy processed by ECAE is reported. Transmission electron microscopy technique involving imaging the regions of such deformation zones with different specimen tilt conditions is used. It is shown that the dynamic recrystallisation occurring in the proximities of second phase particles during the deformation at room temperature, leads to very fine grained microstructure. Observation of multiple active nucleation sites around even sub-micrometer sized non-deformable particles in the as-processed material indicates that the system exhibits efficiency >1 based on the concept of particle stimulated nucleation (PSN). Crystallites of ultra-fine/nanocrystalline size ranges are formed in the deformation zones around the non-deformable particles during deformation itself. Effect of short term post deformation annealing to understand the recovery and recrystallization was undertaken. Based on these results effect of optimal post deformation heat treatment conditions on the thermal stability of the microstructures is emphasized. It is suggested that with significant fraction of non-shearable particles it might be possible to get grain size in the nanocrystalline or ultra-fine range with relatively low effective strain levels using ECAE.


2007 ◽  
Vol 558-559 ◽  
pp. 777-780 ◽  
Author(s):  
Taiki Morishige ◽  
Masato Tsujikawa ◽  
Sung Wook Chung ◽  
Sachio Oki ◽  
Kenji Higashi

Friction stir processing (FSP) is the effective method of the grain refinement for light metals. The aim of this study is to acquire the fine grained bulk Mg-Y-Zn alloy by ingot metallurgy route much lower in cost. Such bulk alloy can be formed by the superplastic forging. The microstructure of as-cast Mg-Y-Zn alloy was dendrite. The dendrite arm spacing was 72.5 [(m], and there are the lamellar structures in it. FSP was conducted on allover the plate of Mg-Y-Zn alloy for both surfaces by the rotational tool with FSW machine. The stirring passes were shifted half of the probe diameter every execution. The dendrite structures disappeared after FSP, but the lamellar structure could be observed by TEM. The matrix became recrystallized fine grain, and interdendritic second phase particles were dispersed in the grain boundaries. By using FSP, cast Mg-Y-Zn alloy could have fine-grained. This result compared to this material produced by equal channel angular extrusion (ECAE) or rapid-solidified powder metallurgy (RS P/M). As the result, as-FSPed material has the higher hardness than materials produced by the other processes at the similar grain size.


2012 ◽  
Vol 29 (1) ◽  
pp. 50
Author(s):  
D.N Ba ◽  
L.T Tai ◽  
N.T Trung ◽  
N.T Huy

The influences of the substitution of Ni with Mg on crystallographic and magnetic properties of the intermetallic alloys LaNi5-xMgx (x ≤ 0.4) were investigated. The X-ray diffraction patterns showed that all samples were of single phase, and the lattice parameters, a and c, decreased slightly upon chemical doping. LaNi5 is well known as an exchange-enhanced Pauli paramagnet. Interestingly, in LaNi5-xMgx, the ferromagnetic order existed even with a small amount of dopants; the Curie temperature reached the value of room temperature for x = 0.2, and enhanced with increasing x.


2013 ◽  
Vol 401-403 ◽  
pp. 610-613
Author(s):  
Jian Ming Wang ◽  
Yang Liu ◽  
Yan Liu ◽  
Qian He Ma

The pipeline steel as an application in pipeline construction must have good comprehensive mechanical properties due to the harsh environment of the pipeline engineering. So this experiment takes the X80 pipeline steel as the research object, the thermal stability second phase particles which would not be dissolved or aggregated at high temperature will be expected by means of adding nanomagnesium oxide into the steel with the method of carrier dispersion addition. The effect of nanometer magnesium oxide addition on the cast microstructure of X80 pipeline steel was analysed. The results show that the cast microstructure is consist of the ferrite and a small amount bainite. And the bainite is distributed at the boundary of the ferrite grains. When adding 0.02 wt% nanometer magnesium oxides, the number of bainite increases significantly in the cast microstructure, which is mostly distributed at the boundary of the ferrite grains.


2020 ◽  
Vol 24 ◽  
pp. 100956
Author(s):  
Fan Zhang ◽  
Yafei Wang ◽  
Yunbiao Duan ◽  
Kaijun Wang ◽  
Yutian Wang ◽  
...  

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