Enhanced thermal stability of nanograined metals below a critical grain size

Science ◽  
2018 ◽  
Vol 360 (6388) ◽  
pp. 526-530 ◽  
Author(s):  
X. Zhou ◽  
X. Y. Li ◽  
K. Lu
Keyword(s):  
Thermal Stability ◽  
Grain Size ◽  
Critical Grain Size ◽  
Thermal Stability Of

Grain Growth in Nanocrystalline Nickel

1999 ◽  
Vol 580 ◽  
Author(s):  
G.D. Hibbard ◽  
U. Erb ◽  
K.T. Aust ◽  
G. Palumbo
Keyword(s):  
Thermal Stability ◽  
Grain Size ◽  
Grain Growth ◽  
Size Distributions ◽  
Nanocrystalline Nickel ◽  
Scanning Calorimetry ◽  
Solute Content ◽  
Grain Size Distributions ◽  
Thermal Stability Of ◽  
Total Solute Content

AbstractIn this study, the effect of grain size distribution on the thermal stability of electrodeposited nanocrystalline nickel was investigated by pre-annealing material such that a limited amount of abnormal grain growth was introduced. This work was done in an effort to understand the previously reported, unexpected effect, of increasing thermal stability with decreasing grain size seen in some nanocrystalline systems. Pre-annealing produced a range of grain size distributions in materials with relatively unchanged crystallographic texture and total solute content. Subsequent thermal analysis of the pre-annealed samples by differential scanning calorimetry showed that the activation energy of further grain growth was unchanged from the as-deposited nanocrystalline nickel.

Thermal Stability of Ultrafine-Grained Pure Titanium Processed by High-Pressure Torsion

2021 ◽  
Vol 1016 ◽  
pp. 338-344
Author(s):  
Wan Ji Chen ◽  
Jie Xu ◽  
De Tong Liu ◽  
De Bin Shan ◽  
Bin Guo ◽  
...  
Keyword(s):  
Activation Energy ◽  
Thermal Stability ◽  
Grain Size ◽  
High Pressure ◽  
Annealing Temperature ◽  
High Pressure Torsion ◽  
Stored Energy ◽  
Ultrafine Grained ◽  
Average Grain Size ◽  
Thermal Stability Of

High-pressure torsion (HPT) was conducted under 6.0 GPa on commercial purity titanium up to 10 turns. An ultrafine-grained (UFG) pure Ti with an average grain size of ~96 nm was obtained. The thermal properties of these samples were studied by using differential scanning calorimeter (DSC) which allowed the quantitative determination of the evolution of stored energy, the recrystallization temperatures, the activation energy involved in the recrystallization of the material and the evolution of the recrystallized fraction with temperature. The results show that the stored energy increases, beyond which the stored energy seems to level off to a saturated value with increase of HPT up to 5 turns. An average activation energy of about 101 kJ/mol for the recrystallization of 5 turns samples was determined. Also, the thermal stability of the grains of the 5 turns samples with subsequent heat treatments were investigated by microstructural analysis and Vickers microhardness measurements. It is shown that the average grain size remains below 246 nm when the annealing temperature is below 500 °C, and the size of the grains increases significantly for samples at the annealing temperature of 600 °C.

The Mechanical Characteristics of Straw/poly(Lactic Acid) Composite Materials

2011 ◽  
Vol 335-336 ◽  
pp. 153-156
Author(s):  
Xue Li Wu ◽  
Jian Hui Qiu ◽  
Lin Lei ◽  
Yang Zhao ◽  
Eiichi Sakai
Keyword(s):  
Thermal Stability ◽  
Grain Size ◽  
Lactic Acid ◽  
Mechanical Characteristics ◽  
Fracture Strain ◽  
Filler Content ◽  
Agricultural Wastes ◽  
Poly Lactic Acid ◽  
Effective Utilization ◽  
Thermal Stability Of

To consider the effective utilization of plastics and agricultural wastes, rice straw fibre was extracted from agricultural wastes, and then composited with polylactic acid(PLA). The thermal stability of straw/poly(lactic acid)(straw/PLA) composites decreased (Thermogravimetric Analysis, TGA). Tensile strength, fracture strain and sharply impact strength of straw/PLA were decreased with the increase of filler content and grain size of straw. Yong’s modulus were increased as the increasing of straw content.

Grain Growth Behaviour Of Nanocrystalline Nickel

1991 ◽  
Vol 238 ◽  
Author(s):  
A. M. El-Sherik ◽  
K. Boylan ◽  
U. Erb ◽  
G. Palumbo ◽  
K. T. Aust
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Grain Size ◽  
Grain Boundary ◽  
Grain Growth ◽  
Thermal Stabilization ◽  
Growth Behaviour ◽  
In Situ Electron Microscopy ◽  
Thermal Stability Of

ABSTRACTThe thermal stability of electrodeposited nanocrystalline Ni-1.2%P and Ni-0.12%S alloys is evaluated by in-situ electron microscopy studies. Isothermal grain size versus annealing time curves at 573K and 623K show an unexpected thermal stabilization in form of a transition from rapid initial grain growth to negligible grain growth. This behaviour is discussed in terms of the various grain boundary drag mechanisms which may be operative in these alloys.

scholarly journals Improved Hardness and Thermal Stability of Nanocrystalline Nickel Electrodeposited with the Addition of Cysteine

Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2254
Author(s):  
Tamás Kolonits ◽  
Zsolt Czigány ◽  
László Péter ◽  
Imre Bakonyi ◽  
Jenő Gubicza
Keyword(s):  
Thermal Stability ◽  
Grain Size ◽  
Dislocation Density ◽  
Nickel Sulfate ◽  
Fault Probability ◽  
Nanocrystalline Nickel ◽  
Twin Fault ◽  
Cysteine Content ◽  
Heating Up ◽  
Thermal Stability Of

Experiments were conducted for the study of the effect of cysteine addition on the microstructure of nanocrystalline Ni films electrodeposited from a nickel sulfate-based bath. Furthermore, the thermal stability of the nanostructure of Ni layers processed with cysteine addition was also investigated. It was found that with increasing cysteine content in the bath, the grain size decreased, while the dislocation density and the twin fault probability increased. Simultaneously, the hardness increased due to cysteine addition through various effects. Saturation in the microstructure and hardness was achieved at cysteine contents of 0.3–0.4 g/L. Moreover, the texture changed from (220) to (200) with increasing the concentration of cysteine. The hardness of the Ni films processed with the addition of 0.4 g/L cysteine (∼6800 MPa) was higher than the values obtained for other additives in the literature (<6000 MPa). This hardness was further enhanced to ∼8400 MPa when the Ni film was heated up to 500 K. It was revealed that the hardness remained as high as 6000 MPa even after heating up to 750 K, while for other additives, the hardness decreased below 3000 MPa at the same temperature.

The influence of crystalline grain size on the thermal stability of the Er0.45Ho0.55Fe2 compound

2002 ◽  
Vol 44 (6) ◽  
pp. 1106-1110 ◽  
Author(s):  
Kh. Ya. Mulyukov ◽  
I. Z. Sharipov ◽  
G. F. Korznikova
Keyword(s):  
Thermal Stability ◽  
Grain Size ◽  
Thermal Stability Of

Effects of the grain size on domain structure and thermal stability of sintered Nd-Fe-B magnets

2018 ◽  
Vol 735 ◽  
pp. 1176-1180 ◽  
Author(s):  
Guangfei Ding ◽  
Shuai Guo ◽  
Ling Chen ◽  
Jinghui Di ◽  
Kan Chen ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Grain Size ◽  
Domain Structure ◽  
Thermal Stability Of

Microstructure and Thermal Stability of Copper - Carbon Nanotube Composites Consolidated by High Pressure Torsion

2012 ◽  
Vol 729 ◽  
pp. 228-233 ◽  
Author(s):  
P. Jenei ◽  
E.Y. Yoon ◽  
Jenő Gubicza ◽  
Hyoung Seop Kim ◽  
J.L. Lábár ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Grain Size ◽  
High Pressure ◽  
Dislocation Density ◽  
High Pressure Torsion ◽  
Lattice Defect ◽  
Taylor Formula ◽  
Processing Temperature ◽  
Pure Cu ◽  
Thermal Stability Of

Blends of Cu powders and 3 vol. % carbon nanotubes (CNTs), and an additional sample from pure Cu powder were consolidated by High Pressure Torsion (HPT) at room temperature (RT) and 373 K. The grain size, the lattice defect densities as well as the hardness of the pure and composite materials were determined. Due to the pinning effect of CNTs, the dislocation density is about three times larger, while the grain size is about half of that obtained in the sample consolidated from the pure Cu powder. The increase of the HPT-processing temperature from RT to 373 K resulted in only a slight increase of the grain size in the Cu-CNT composite while the dislocation density and the twin boundary frequency were reduced significantly. The flow stress obtained experimentally agrees well with the value calculated by the Taylor-formula indicating that the strength in both pure Cu and Cu-CNT composites is determined mainly by the interaction between dislocations. The addition of CNTs to Cu yields a significantly better thermal stability of the UFG matrix processed by HPT.

scholarly journals Thermal Stability of Nanocrystalline Gradient Inconel 718 Alloy

Crystals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 53
Author(s):  
Jie Ding ◽  
Yifan Zhang ◽  
Tongjun Niu ◽  
Zhongxia Shang ◽  
Sichuang Xue ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Grain Size ◽  
Inconel 718 ◽  
Treatment Technique ◽  
Mechanical Grinding ◽  
Inconel 718 Alloy ◽  
Transmission Electron ◽  
Nickel Based Alloy ◽  
Energy Configurations ◽  
Thermal Stability Of

Gradient structures containing nanograins in the surface layer have been introduced into Inconel 718 (IN718) nickel-based alloy using the surface mechanical grinding treatment technique. The thermal stability of the gradient IN718 alloy was investigated. Annealing studies reveal that nanograins with a grain size smaller than 40 nm exhibited significantly better thermal stability than those with larger grain size. Transmission electron microscopy analyses reveal that the enhanced thermal stability was attributed to the formation of grain boundaries with low energy configurations. This study provides new insight on strategies to improve the thermal stability of nanocrystalline metals.

Sign in / Sign up

Export Citation Format

Share Document