Investigation on Microstructure and Properties of Heavily Cold Rolled Cu-Fe Alloys

2010 ◽  
Vol 150-151 ◽  
pp. 847-851
Author(s):  
Zhi Ming Zhou ◽  
Li Wen Tang ◽  
Min Min Cao ◽  
Bin Bin Lei

CuFe10 and CuFe15 (mass fraction) alloys were prepared by vacuum induction melting and were cold rolled heavily at room temperature. Microstructure, microhardness and electrical conductivity of these alloys were measured at various cold rolled strain levels. The experimental results showed that the microhardness increased rapidly and the electrical conductivity decreases gradually with the increase of rolling strain at first. The microhardness increased slowly while the strain η greater than 2.3. The Fe-rich phases are deformed to ribbons filaments. However, the electrical conductivity increases again after deforming to a certain degree. The final electrical conductivities of heavily cold rolled CuFe10 and CuFe15 alloys were slight lower than vacuum inducing melted master alloys, however, the microhardness had increased about 44% and 47%, respectively.

2021 ◽  
Vol 1035 ◽  
pp. 89-95
Author(s):  
Chao Tan ◽  
Zi Yong Chen ◽  
Zhi Lei Xiang ◽  
Xiao Zhao Ma ◽  
Zi An Yang

A new type of Ti-Al-Sn-Zr-Mo-Si series high temperature titanium alloy was prepared by a water-cooled copper crucible vacuum induction melting method, and its phase transition point was determined by differential thermal analysis to be Tβ = 1017 °C. The influences of solution temperature on the microstructures and mechanical properties of the as-forged high temperature titanium alloy were studied. XRD results illustrated that the phase composition of the alloy after different heat treatments was mainly α phase and β phase. The microstructures showed that with the increase of the solution temperature, the content of the primary α phase gradually reduced, the β transformation structure increased by degrees, then, the number and size of secondary α phase increased obviously. The tensile results at room temperature (RT) illustrated that as the solution temperature increased, the strength of the alloy gradually increased, and the plasticity decreased slightly. The results of tensile test at 650 °C illustrated that the strength of the alloy enhanced with the increase of solution temperature, the plasticity decreased first and then increased, when the solution temperature increased to 1000 °C, the alloy had the best comprehensive mechanical properties, the tensile strength reached 714.01 MPa and the elongation was 8.48 %. Based on the room temperature and high temperature properties of the alloy, the best heat treatment process is finally determined as: 1000 °C/1 h/AC+650 °C/6 h/AC.


2018 ◽  
Author(s):  
Sahand Faraji ◽  
Behnam Sadri ◽  
Babak Vajdi Hokmabad ◽  
Esmaeil Esmaeilzadeh ◽  
Navid Jadidoleslam

In the present experimental study, the effects of electrical conductivity on electrospraying procedure are investigated.A metallic nozzle with 600 m ID as high voltage electrode and a stainless steel ring as a groundelectrode were employed. Experiments were carried out in still room temperature. Four different aqueous KClsolutions were sprayed in various high voltages and flow rates. Results confirm that spraying modes changeswith conductivity variation. For forming a cone shape, emerging from the nozzle, required applied electric fielddecreases with conductivity increasing. Results also revealed that conductivity of dispersed solution acts a mainrole on forming and elongation of the cones in electrospraying procedure. The size and velocity of emanateddroplets are also investigated in order to gaining some insight to the electrospraying phenomenon.


2012 ◽  
Vol 710 ◽  
pp. 119-124 ◽  
Author(s):  
Niraj Nayan ◽  
S.V.S. Narayana Murty ◽  
S.C. Sharma ◽  
K. Sreekumar ◽  
P.P. Sinha

The objective of the present study was to melt and cast AA2195 alloy in Vacuum Induction Melting (VIM) under dynamic inert atmosphere. These billets were homogenized and subsequently hot forged and rolled to sheets. The products in the form of sheets were subjected to T8 (Solution Treatment +WQ+CW+Aging) temper condition. Mechanical properties were evaluated at room temperature and correlated with microstructure. Highest mechanical properties obtained in T87 temper have been reported.


2015 ◽  
Vol 830-831 ◽  
pp. 15-18
Author(s):  
V. Anil Kumar ◽  
M.K. Karthikeyan ◽  
Rohit Kumar Gupta ◽  
M. Amruth ◽  
P. Ram Kumar ◽  
...  

15Cr-5Ni-1W precipitation hardening (PH) stainless steel is a martensitic PH stainless steel finding extensive use in semi-cryo engine applications. The alloy was developed through Vacuum Induction Melting (VIM) + Electro slag refining (ESR) under argon cover route. The alloy contains heavy elements like Mo, Nb, V and W totalling ~ 2 % by weight. Since the alloy is martensitic, stringent gas levels were also specified. Hence it was a challenging task to realise it without any segregation and stringent gas levels. The alloy was successfully melted through two different melt routes – (C). Electric Arc melting followed by Vacuum Oxygen decarburization (VOD) - vacuum degassing (VD) followed by secondary melting by ESR and also by melt route (V) vacuum induction melting (VIM) + ESR route. It was then forged into bars, rods and rings. The samples from the alloy were subjected to two different heat treatment cycles. Both the heat treatment cycles involved hardening at 1000°C for 2 hrs followed by air cooling to room temperature. In one of the cycle, sub-zero heat treatment at-70 °C was done prior to tempering while in the other cycle; direct tempering was carried out after hardening operation. Tempering was carried out at 2 different temperatures of 490 and 500 °C to achieve the specified mechanical properties. It was found that the alloy could meet the specified strength and ductility with both the heat treatment cycles mentioned above. However samples subjected to subzero heat treatment showed marginally higher strength with slight compromise in ductility. The alloy also exhibited similar impact toughness in both the heat treatment conditions. Delta ferrite was also found to be within 2% for both the heat treatment cycles employed in this study. The alloy also exhibited excellent strength and ductility at elevated temperature of 500 °C with just 25% reduction in yield strength compared to room temperature yield strength without much change in ductility.


2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Wenbo Qin ◽  
Jiansheng Li ◽  
Yaoyao Liu ◽  
Wen Yue ◽  
Chengbiao Wang ◽  
...  

The mechanical and tribological performances of 316 L stainless steel subjected to different cold rolling (CR) strains were investigated. The microhardness and strength of 316 L stainless steel were improved attributed to the formation of high-density defects, such as dislocations and parallel lamellar structures. Furthermore, the tribology tests were conducted under dry sliding at room temperature. With the increase in rolling strain, the wear rate of 316 L stainless steel gradually decreased due to the improvements in microhardness and strength. For the as-received specimen, the strong adhesive wear leads to the maximum wear rate compared with the cold rolled specimens. Under higher rolling strain conditions, the grain boundary embrittlement caused by oxygen reaction leads to the formation of oxidative abrasive under dry sliding conditions, and then the oxidative abrasive could serve as the third body at the siding interface. Consequently, there is a transition phase where the wear mechanism gradually shifts from adhesive to abrasive wear.


1997 ◽  
Vol 488 ◽  
Author(s):  
R. C Hyer ◽  
R. G. Pethe ◽  
T. Yogi ◽  
S. C. Sharma ◽  
J. Wang ◽  
...  

AbstractWe present results for the electrical conductivity (σ) of thin films of poly(benzo[1,2-b:4,5- b']dithiophene-4,8-diyl vinylene) (PBDV) and poly (dodecylthiophene) (PDDT) as a function of temperature in the range 15-295K. The polymers were doped with FeC13 and PF6 which resulted in electrical conductivities differing by two orders of magnitude at room temperature. We examine three sets of σ(T)-data by using the variable-range hopping (VRH) model that predicts a linear relationship between ln(T1/2σ) and T1/4. We observe a change in the slope of the ln(T1/2σ) vs T14 relationship in all three samples at low temperatures. We also analyze the temperature dependence of the resistivity of PBDV by using the thermal fluctuation-induced tunneling model.


1983 ◽  
Vol 30 ◽  
Author(s):  
E. Pfender

In general, a plasma consists of a mixture of electrons, ions,and neutral species. Although there are free electric charges in a plasma, negative and positive charges compensate each other, i.e. overall a plasma is electrically neutral, a property which is known as quasi-neutrality. In contrast to an ordinary gas, the free electric charges in a plasma give rise to high electrical conductivities which may even surpass those of metals. A hydrogen plasma, for example, at atmospheric pressure heated to temperatures of 106 K, has the same electrical conductivity as copper at room temperature. As the plasma temperature increases, the electrical conductivity increases beyond that of copper. Plasma temperatures of the order of 106 K and above are typical for thermonuclear fusion experiments.


Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 5994
Author(s):  
Enrico Gianfranco Campari ◽  
Angelo Casagrande ◽  
Elena Colombini ◽  
Magdalena Lassinantti Gualtieri ◽  
Paolo Veronesi

The effect of Zr addition on the melting temperature of the CoCrFeMnNi High Entropy Alloy (HEA), known as the “Cantor’s Alloy”, is investigated, together with its micro-structure, mechanical properties and thermomechanical recrystallization process. The base and Zr-modified alloys are obtained by vacuum induction melting of mechanically pre-alloyed powders. Raw materials are then cold rolled and annealed. recrystallization occurred during the heat treatment of the cold-rolled HEA. The alloys are characterized by X-ray diffraction, electron microscopy, thermal analyses, mechanical spectroscopy and indentation measures. The main advantages of Zr addition are: (1) a fast vacuum induction melting process; (2) the lower melting temperature, due to Zr eutectics formation with all the Cantor’s alloy elements; (3) the good chemical alloy homogeneity; and (4) the mechanical properties improvement of re-crystallized grains with a coherent structure. The crystallographic lattice of both alloys results in FCC. The Zr-modified HEA presents a higher recrystallization temperature and smaller grain size after recrystallization with respect to the Cantor’s alloy, with precipitation of a coherent second phase, which enhances the alloy hardness and strength.


2012 ◽  
Vol 710 ◽  
pp. 125-131 ◽  
Author(s):  
Niraj Nayan ◽  
S.V.S. Narayana Murty ◽  
S.C. Sharma ◽  
K. Sreekumar ◽  
Parameshwar Prasad Sinha

A novel technique of pure Lithium addition has been adopted for the processing of Al-Cu-Li alloy AA2195 cast ingots (7-8 kg each) in VIM under dynamic inert atmosphere, which gives more than 95% recovery of Lithium. The cast billets were homogenized, forged and converted into 12mm diameter rods by caliber rolling in the temperature range of 250°C, 300°C, 350°C and 400°C. The caliber rolled rods were treated to T8 (Solution Treatment+WQ+CW+Aging) condition. Mechanical properties were evaluated for T8 tempered bars at room temperature and correlated with microstructural observations. Highest mechanical properties in T87 temper have been obtained for rods caliber rolled at 350°C temperature.


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