Self-diffusion of an asymmetric diblock copolymer above and below the order-to-disorder transition temperature

1999 ◽  
Vol 111 (6) ◽  
pp. 2789-2796 ◽  
Author(s):  
Gerald Fleischer ◽  
Frank Rittig ◽  
Jörg Kärger ◽  
Christine M. Papadakis ◽  
Kell Mortensen ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Diblock Copolymer ◽  
Disorder Transition ◽  
Self Diffusion ◽  
Disorder Transition Temperature

Effect of Atomic Order on Iron and Cobalt Grain Boundary Diffusion in the FeCo Equiatomic Compound

1998 ◽  
Vol 527 ◽  
Author(s):  
Zs. Tôkei ◽  
J. Bernardini ◽  
D. L. Beke
Keyword(s):  
Transition Temperature ◽  
Grain Boundary ◽  
Surface Segregation ◽  
Diffusion Activation Energy ◽  
Kinetic Regime ◽  
Exponential Factor ◽  
Disorder Transition ◽  
Self Diffusion ◽  
Diffusion Activation ◽  
Disorder Transition Temperature

ABSTRACTSimultaneous grain boundary self-diffusion of iron and cobalt in FeCo was investigated in the B-kinetic regime by the radiotracer method combined with a serial sectioning technique over the temperature range 873-1133 K, which includes the A2-B2 bulk order-disorder transition temperature. This transition leads to a decrease in both iron and cobalt mass transport mainly owing to a change in the pre-exponential factor, but not in the diffusion activation energy. Moreover, the breaking point in the Arrhenius plots is observed below the bulk order-disorder transition temperature. In view of recent surface segregation studies on Fe-Co, and according to the Fe-Co phase diagram, the results are discussed assuming an iron segregation, which decreases the A2-B2 transition temperature in grain boundaries.

Anomalous Difference in the Order−Disorder Transition Temperature Comparing a Symmetric Diblock Copolymer AB with Its Hetero-Four-Arm Star Analog A2B2

1999 ◽  
Vol 32 (22) ◽  
pp. 7483-7495 ◽  
Author(s):  
D. M. A. Buzza ◽  
I. W. Hamley ◽  
A. H. Fzea ◽  
M. Moniruzzaman ◽  
J. B. Allgaier ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Diblock Copolymer ◽  
Disorder Transition ◽  
Disorder Transition Temperature

scholarly journals Alloying effect on the order–disorder transformation in tetragonal FeNi

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Li-Yun Tian ◽  
Oliver Gutfleisch ◽  
Olle Eriksson ◽  
Levente Vitos
Keyword(s):  
Transition Temperature ◽  
High Performance ◽  
Density Functional ◽  
Permanent Magnets ◽  
Positive Impact ◽  
Design Strategies ◽  
Alloying Effect ◽  
Functional Theory ◽  
Disorder Transition ◽  
Disorder Transition Temperature

AbstractTetragonal ($${\hbox{L1}}_{0}$$ L1 0 ) FeNi is a promising material for high-performance rare-earth-free permanent magnets. Pure tetragonal FeNi is very difficult to synthesize due to its low chemical order–disorder transition temperature ($$\approx {593}$$ ≈ 593  K), and thus one must consider alternative non-equilibrium processing routes and alloy design strategies that make the formation of tetragonal FeNi feasible. In this paper, we investigate by density functional theory as implemented in the exact muffin-tin orbitals method whether alloying FeNi with a suitable element can have a positive impact on the phase formation and ordering properties while largely maintaining its attractive intrinsic magnetic properties. We find that small amount of non-magnetic (Al and Ti) or magnetic (Cr and Co) elements increase the order–disorder transition temperature. Adding Mo to the Co-doped system further enhances the ordering temperature while the Curie temperature is decreased only by a few degrees. Our results show that alloying is a viable route to stabilizing the ordered tetragonal phase of FeNi.

Increased Order–Disorder Transition Temperature for a Rod–Coil Block Copolymer in the Presence of a Magnetic Field

2011 ◽  
Vol 44 (19) ◽  
pp. 7503-7507 ◽  
Author(s):  
Bryan McCulloch ◽  
Giuseppe Portale ◽  
Wim Bras ◽  
Rachel A. Segalman
Keyword(s):  
Magnetic Field ◽  
Transition Temperature ◽  
Block Copolymer ◽  
Disorder Transition ◽  
Disorder Transition Temperature
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