alloying effect
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2022 ◽  
Vol 580 ◽  
pp. 121391
Liqiao Yue ◽  
Qijing Sun ◽  
Yihao Wang ◽  
Yin Wang ◽  
Rongjie Xue ◽  

2021 ◽  
Chun-Mei Li ◽  
Shun-Jie Yang ◽  
Jin-Ping Zhou

Abstract The alloying and magnetic disordering effects on the site occupation, elastic property, and phase stability of Co2 YGa (Y=Cr, V, and Ni) shape memory alloys are systematically investigated by using the first-principles exact muffin-tin orbitals method. It is shown that with increasing the magnetic disordering degree (y), their tetragonal shear elastic constant C' ((C 11 - C 12)/2) of the L21 phase decreases whereas the elastic anisotropy (A) increases, and upon tetragonal distortions the cubic phase gets more and more unstable. Co2CrGa and Co2VGa alloys with y ≥ 0.2 thus can show the martensitic transformation (MT) from L21 to D022 as well as Co2NiGa. In off-stoichiometric alloys, the site preference is controlled by both the alloying and magnetic effects. At the FM state, the excess Ga atom always tends to take the Y sublattice, whereas the excess Co atom favors the Y site when Y=Cr, and the excess Y atom prefers the Co site when Y=Ni. The Ga-deficient Y=V alloys can occur the MT also at the FM state by means of Co or V doping, and the MT temperature (T M ) should increase with their addition. In the corresponding FM Y=Cr alloys, nevertheless, with Co or Cr substituting for Ga, the reentrant MT (RMT) from D022 to L21 is promoted and then T M for the RMT should decrease. The alloying effect on the MT of these alloys is finally well explained by means of the Jahn-Teller effect at the paramagnetic (PM) state. At the FM state, it may originate from the competition between the austenite and martensite about their strength of the covalent banding between Co and Ga as well as Y and Ga.

2021 ◽  
Vol 62 (10) ◽  
pp. 1541-1548
Nicharee Wongsawatgul ◽  
Soamwadee Chaianansutcharit ◽  
Kazuhiro Yamamoto ◽  
Makoto Nanko ◽  
Kazunori Sato

2021 ◽  
Olga K. Rowan ◽  
Michael A. Pershing

Abstract Nitriding surface hardening is commonly used on steel components for high wear, fatigue and corrosion applications. Case hardening results from white layer formation and coherent alloy nitride precipitates in the diffusion zone. This paper evaluates the microstructure development in the nitrided case and its effects on the hardness in both the white layer and the substrate for two industry nitriding materials, Nitralloy 135M and AISI 4140. Computational thermodynamic calculations were used to identify the type and amount of stable alloy nitrides precipitation and helped explain the differences in the white layer hardness, degree of porosity at the surface, and the hardening effect within the substrate. Some initial insights toward designing nitriding alloys are shown.

2021 ◽  
Haibo Yin ◽  
Zhen Chen ◽  
Shangchao Xiong ◽  
Jianjun Chen ◽  
Chizhong Wang ◽  

2021 ◽  
Vol 31 (9) ◽  
pp. 2750-2761
Da-wei DING ◽  
An-hui CAI ◽  
Yong LIU ◽  
Hong WU ◽  

2021 ◽  
Vol 1037 ◽  
pp. 494-502
Zhesfina Michailovna Blednova ◽  
Etibar Yusif O. Balaev ◽  
Anna Pavlovna Yurkova

The article presents the assessment study of mechanical activation and mechanical alloying effect on the structure, phase state of the powder composition and of the coating based on it. The duration of mechanical activation was varied as follows: 1 h, 2 h, 4 h, 8 h, 16 h, 32 h. It is shown that in order to from a high-entropy FeNiCoAlNb alloy on the workpiece surface the duration of mechanical activation must be at least 4 hours. We described the mechanism of mechanical alloying and ways of accelerating this process.

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