Effect of Bi Addition on Thermal Stability and Tensile Ductility of Mg-3%Zn-0.4%Zr Alloy

2010 ◽  
Vol 654-656 ◽  
pp. 647-650
Author(s):  
Joong Hwan Jun ◽  
Min Ha Lee

Thermal stability of  grains and tensile ductilities at room and elevated temperatures were investigated and compared for Mg-3%Zn-0.4%Zr and Mg-3%Zn-0.4%Zr-1%Bi alloys in hot-rolled state. The Bi-added alloy showed slightly finer-grained microstructure with enhanced thermal stability, which is closely associated with fine Mg-Bi compounds acting as obstacles for the migration of grain boundaries. The Mg-3%Zn-0.4%Zr-1%Bi alloy exhibited better tensile strength at room temperature and tensile ductilities at elevated temperature. Finer and more homogeneous grain structure with higher thermal stability would be responsible for the enhanced tensile properties in the Bi-added alloy.

2017 ◽  
Vol 71 (12) ◽  
pp. 2626-2631 ◽  
Author(s):  
Jeffrey L. Wheeler ◽  
McKinley Pugh ◽  
S. Jake Atkins ◽  
Jason M. Porter

In this work, the thermal stability of the room temperature ionic liquid (RTIL) 1-ethyl-3-methylimidazolium ethylsulfate ([EMIM][EtSO4]) is investigated using infrared (IR) spectroscopy. Quantitative IR absorption spectral data are measured for heated [EMIM][EtSO4]. Spectra have been collected between 25 ℃ and 100 ℃ using a heated optical cell. Multiple samples and cell pathlengths are used to determine quantitative values for the molar absorptivity of [EMIM][EtSO4]. These results are compared to previous computational models of the ion pair. These quantitative spectra are used to measure the rate of thermal decomposition of [EMIM][EtSO4] at elevated temperatures. The spectroscopic measurements of the rate of decomposition show that thermogravimetric methods overestimate the thermal stability of [EMIM][EtSO4].


Author(s):  
Stephanie Saalfeld ◽  
Thomas Wegener ◽  
Berthold Scholtes ◽  
Thomas Niendorf

AbstractThe stability of compressive residual stresses generated by deep rolling plays a decisive role on the fatigue behavior of specimens and components, respectively. In this regard, deep rolling at elevated temperature has proven to be very effective in stabilizing residual stresses when fatigue analysis is conducted at ambient temperature. However, since residual stresses can be affected not only by plastic deformation but also when thermal energy is provided, it is necessary to analyze the influence of temperature and time on the relaxation behavior of residual stresses at elevated temperature. To evaluate the effect of deep rolling at elevated temperatures on stability limits under thermal as well as combined thermo-mechanical loads, the present work introduces and discusses the results of investigations on the thermal stability of residual stresses in differently deep rolled material conditions of the steel SAE 1045.


1989 ◽  
Vol 173 ◽  
Author(s):  
Michiya Otani ◽  
Sugio Otani

ABSTRACTThe stability of the magnetic properties of dehydrogenated triaryl-methane resins was investigated both at room temperature and at elevated temperatures. A magnetic property different from that reported in a previous paper was found in the course of studying the reproducibility of synthesis. This new property was examined through a mechanical response of the resins to a set of permanent magnets.


Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1498 ◽  
Author(s):  
Jie Zhou ◽  
Fang Ye ◽  
Xuefeng Cui ◽  
Laifei Cheng ◽  
Jianping Li ◽  
...  

The mechanical and dielectric properties of two types of amorphous silicon nitride (Si3N4) fibers prior to and following annealing at 800 °C were studied. The tensile strengths of the Si3N4 fiber bundles were measured using unidirectional tensile experimentation at room temperature, whereas the permittivity values were measured at 8.2–12.4 GHz using the waveguide method. The results demonstrated that the tensile strength and dielectric properties of Si3N4 fibers were correlated to the corresponding composition, microstructure, and intrinsic performance of electrical resistance. The Si3N4 fibers with a lower content of amorphous SiNxOy presented an improved thermal stability, a higher tensile strength, a higher conductivity, and a significantly stable wave-transparent property. These were mainly attributed to the highly pure composition and decomposition of less amorphous SiNxOy.


2015 ◽  
Vol 662 ◽  
pp. 19-22
Author(s):  
Kornel Csach ◽  
Jozef Miškuf ◽  
Alena Juríková ◽  
Maria Hurakova ◽  
Václav Ocelík ◽  
...  

Nanoindentation and thermomechanical experiments on three types of metallic glasses with different glass forming ability were carried out. The nanoindentation behaviour at room temperature was associated with the creep at elevated temperatures. Different discontinuity populations and their shape observed on the nanoindentation loading curves were compared with morphology of plastic deformed indent regions. The influence of the differences in thermal stability of studied alloys on the nanoindentation in these alloys were studied as well.


Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1648
Author(s):  
Guo-Jun Liu ◽  
Yan-Hua Sun ◽  
Nan Xia ◽  
Xiao-Fang Guan

The effects of small amounts of Ce-rich misch metal (Mm: 0.5, 1.0 and 2.0 wt.%) addition on the microstructure and tensile properties of as-cast Mg-7Al-3Sn-1Zn wt.% (ATZ731) alloy have been investigated. The addition of Mm restricts the formation of the Mg17Al12 phase but greatly promotes the Al4Mm phase. The proper Mm addition enhances the strength and ductility of ATZ731 alloys at both room temperature (RT) and 175 °C. ATZ731 alloys with 1.0 wt.% Mm addition exhibit an advantageous combination strength and ductility, with the ultimate tensile strength (UTS), 0.2% yield strength (YS) and elongation to failure (Ef) at 175 °C of ~148 MPa, ~102 MPa and ~28%, improved by ~14.7%, ~24.3% and ~53.8%, respectively, compared to those of ATZ731 alloy. This enhancement is primarily owing to the refined microstructures and the high thermal stability of Al4Mm at the elevated temperature in contrast with that of the Mg17Al12 phase. The fracture modes are also discussed.


2018 ◽  
Vol 385 ◽  
pp. 273-277
Author(s):  
Elena Sarkeeva ◽  
Marina M. Abramova ◽  
Igor V. Alexandrov

The article studies an influence of temperature of severe plastic deformation (SPD) and post-deformation heat treatment on microstructure, mechanical properties and thermal stability of the Cu-0.5Cr-0.2Zr alloy. The results demonstrate that strength is considerably increased to 900 MPa by high pressure torsion (HPT) at room temperature. Subsequent ageing at 450 °С during 1 hour leads to a decay of solid solution and an allocation of dispersion particles that further incrises strength to 900 MPa, restores electrical conductivity to 70% IACS (International annealed copper standard) and enhances thermal stability of the alloy. When deformation temperature is increased to 300°С, strength is 690 MPa that is lower than in the case of deformation at room temperature that is related to reversion process at deformation. Additional a aging does not lead to an increase of strength characteristics.


2016 ◽  
Vol 51 (18) ◽  
pp. 2643-2653 ◽  
Author(s):  
Jian Qin ◽  
Zhan Zhang ◽  
X-Grant Chen

The microstructure, mechanical properties, thermal stability and tensile fracture of two hot-rolled Al-15 vol.% B4C composite sheets (S40 with 0.4 wt.% Sc and SZ40 with 0.4 wt.% Sc and 0.24 wt.% Zr) were investigated. During multi-pass hot rolling, coarse Al3Sc or Al3(Sc, Zr) precipitations appeared and resulted in the loss of most of their hardening effect. In an appropriate post-rolling heat treatment, the hot-rolled sheets regained a significant precipitation hardening because of the precipitation of fine nanoscale Al3Sc and Al3(Sc,Zr) that uniformly distributed in the aluminum matrix. After the peak aging, the ultimate tensile strength at ambient temperature of the S40 and SZ40 sheets can reach 198 MPa and 215 MPa, respectively. During 2000 h of annealing at 300℃, the strengths at ambient temperature of both S40 and SZ40 composite sheets slowly decreased with increasing annealing time. However, the tensile strengths at 300℃ of both S40 and SZ40 composite sheets remained nearly unchanged and were less sensitive to the annealing time and more tolerable for precipitate coarsening, which demonstrated an excellent long-term thermal stability of both materials at elevated temperature. The tensile fracture at ambient temperature of both S40 and SZ40 composite sheets was dominated by the brittle B4C particle fracture, whereas the interfacial decohesion of B4C particles became the prominent characteristic of the fracture at 300℃.


2014 ◽  
Vol 998-999 ◽  
pp. 51-54
Author(s):  
Qing Zhang ◽  
Quan An Li ◽  
Jun Chen ◽  
Xing Yuan Zhang

The enhanced dispersion strengthening of Sm in Mg-10Y-0.5Sm has been investigated by means of microstructure analysis and tensile tests. The results show that Sm addition improves the image of Mg24Y5 phase and causes the formation of fine and dispersed Mg24Y5 phase. Meanwhile, the dissolved Sm increases the thermal stability of Mg24Y5 phase and enhances its dispersion strengthening in the alloy. It leads to the increased tensile strength of the alloy at elevated temperatures.


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.


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