Effect of S on H-induced grain-boundary embrittlement in γ-Fe by first-principles calculations

2021 ◽  
Author(s):  
Yang He ◽  
Xiong Zhao ◽  
Haobo Yu ◽  
Changfeng Chen
Keyword(s):  
Grain Boundary ◽  
First Principles ◽  
First Principles Calculations ◽  
Grain Boundary Embrittlement ◽  
Boundary Embrittlement

Solute Segregation at Σ11(113)[110] Grain Boundary and Effect of the Segregation on Grain Boundary Cohesion in Aluminum from First Principles

2010 ◽  
Vol 654-656 ◽  
pp. 942-945 ◽  
Author(s):  
Tokuteru Uesugi ◽  
Kenji Higashi
Keyword(s):  
Free Surface ◽  
Grain Boundary ◽  
First Principles ◽  
Solute Segregation ◽  
First Principles Calculations ◽  
Symmetric Tilt ◽  
Tilt Grain Boundary ◽  
Grain Boundary Embrittlement ◽  
Boundary Embrittlement

We investigate the energy of segregation of solute Ca at symmetric tilt grain boundary in aluminum from the first-principles calculations. As energy of segregation of Ca is negative, Ca atoms tend to segregate at the grain boundary. Furthermore, on basis of the Rice-Wang model, we study the effect of the segregation of Ca on the grain boundary embrittlement of aluminum. Our first-principles calculations of energies of segregation at grain boundary and free surface show that Ca behaves as embrittler.

Grain Boundary Embrittlement of Fe Induced by P Segregation: First-Principles Tensile Tests

2011 ◽  
Vol 409 ◽  
pp. 455-460 ◽  
Author(s):  
Motohiro Yuasa ◽  
Mamoru Mabuchi
Keyword(s):  
Tensile Strength ◽  
Grain Boundary ◽  
First Principles ◽  
Tensile Tests ◽  
Bond Breaking ◽  
Charge Densities ◽  
Grain Boundary Embrittlement ◽  
Boundary Embrittlement

The GB embrittlement mechanism of Fe enhanced by P segregation has been investigated by first-principles tensile tests because a P atom is a famous GB embrittler in Fe. The first-principles tensile tests have been performed on Fe with two P-segregated GBs, where P atoms are located at the different sites, and with a nonsegregated GB. The tensile strength and the strain to failure in the P-segregated GBs were lower than those in the nonsegegated GB. The first bond breaking occurred at the Fe-P bond owing to the covalent-like characteristics, although the charge densities were high at the Fe-P bonds even just before the bond breaking. This premature bond breaking of Fe-P was independent of the location of the P atom.

Al Grain Boundary Embrittlement Promoted by Na Impurity: An ab initio Study

2000 ◽  
Vol 653 ◽  
Author(s):  
Guang-Hong Lu ◽  
Masanori Kohyama ◽  
Rayoichi Yamamoto
Keyword(s):  
Electronic Structure ◽  
Grain Boundary ◽  
Charge Density ◽  
First Principles ◽  
Ab Initio Study ◽  
Impurity Atoms ◽  
Metallic Bond ◽  
Tilt Grain Boundary ◽  
Grain Boundary Embrittlement ◽  
Boundary Embrittlement

AbstractWe calculate the electronic structure of AlΣ9 tilt grain boundary with substitutional Na impurity atoms by first principles pseudopotential method. Results show that by Na segregation Al grain boundary expands and the valence charge density decreases significantly along the boundary. There is no stronger bond than metallic bond in the boundary even with Na impurity. We therefore conclude that the mechanism of Na-promoted Al grain boundary embrittlement should be one kind of ‘decohesion model’.

scholarly journals Research Progress of the Effects of Trace S Element on the Microstructure of Cast Nickel-base Superalloys

2021 ◽  
Vol 299 ◽  
pp. 02004
Author(s):  
Chenguang Liu ◽  
Huan Xu ◽  
Hui Zhang ◽  
Peiyuan Liu ◽  
Gong Yang ◽  
...  
Keyword(s):  
Adverse Effects ◽  
Grain Boundary ◽  
First Principles ◽  
Research Progress ◽  
Microstructure And Properties ◽  
Nickel Base Superalloys ◽  
Grain Boundary Embrittlement ◽  
Nickel Base ◽  
Experimental Researches ◽  
Boundary Embrittlement

In the process of alloy melting and vacuum pouring, the impurity S element will inevitably be introduced into the nickel-base superalloys, which will cause adverse effects on the microstructure and properties of the cast nickel-base superalloys. In this paper, the research progress of S element in cast nickel-base superalloys is summarized. The effects of S element on the microstructure are described in detail from experimental researches and first-principles. The reasons for the grain boundary embrittlement caused by S atom are discussed, and the authors wish to provide some references for the better development of cast nickel-base superalloys.

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