scholarly journals New Approach to Produce a Nanocrystalline Layer on Surface of a Large Size Pure Titanium Plate

Coatings ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 430
Author(s):  
Yuzhu Fu ◽  
Ge Wang ◽  
Jing Gao ◽  
Quantong Yao ◽  
Weiping Tong
Keyword(s):  
Pure Titanium ◽  
Grain Morphology ◽  
Optical Microscope ◽  
Surface Mechanical Attrition Treatment ◽  
Titanium Plate ◽  
Hardness Tester ◽  
Large Size ◽  
Transmission Electron ◽  
Average Grain Size ◽  
Nanocrystalline Layer

It was demonstrated that the mechanical shot peening (MSP) technique was a viable way to obtain a nanocrystalline layer on a large size pure titanium plate due to the MSP provided for severe plastic deformation (SPD) of surface high velocity balls impacting. The MSP effects of various durations in producing the surface nanocrystalline layer was characterized by optical microscope (OM), X-ray diffraction (XRD), transmission electron microscope (TEM), and Vickers micro-hardness tester. The results showed that the thickness of the SPD layer gradually increased with the MSP processing time increase, but saturated at 230 μm after 30 min. The average grain size was refined to about 18.48 nm in the nanocrystalline layer. There was equiaxed grain morphology with random crystallographic orientation in the topmost surface. By comparing with the nanocrystalline layer, acquired by surface mechanical attrition treatment (SMAT), the microstructure and properties of the nanocrystalline layer acquired by MSP was evidently superior to that of the SMAT, but the production time was cut to about a quarter of the time used for the SMAT method.

Thermal Stability of Nanocrystalline Ti6Al4V Produced by Surface Mechanical Attrition Treatment

2017 ◽  
Vol 898 ◽  
pp. 41-46
Author(s):  
Quan Tong Yao ◽  
Meng Nan Xing ◽  
Guang Lan Zhang ◽  
Wei Ping Tong
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Pure Titanium ◽  
Surface Mechanical Attrition Treatment ◽  
X Ray ◽  
Transmission Electron ◽  
Mechanical Attrition ◽  
Nanocrystalline Layer ◽  
Thermal Stability Of ◽  
Scanning Electron

A pollution-free nanocrystalline layer was prepared on the surface of Ti6Al4V by surface mechanical attrition treatment (SMAT). The nanocrystalline samples were vacuum annealed at various temperatures and for different periods of time. The microstructure and thermal stability were characterized by X-ray (XRD), scanning electron microscopy (SEM) and, transmission electron microscopy (TEM). The results showed that the nanocrystalline Ti6Al4V presented a satisfactory thermal stability with the annealed temperature below 650°C. The critical growth temperature for nanocrystalline Ti6Al4V is 100°C higher than that for pure titanium.

Evolutions of Microstructure for Multilayered Al-Mg Alloy Composites by Accumulation Roll Bonding (ARB) Process

2011 ◽  
Vol 411 ◽  
pp. 527-531
Author(s):  
Bing Zhang ◽  
Zhong Wei Chen ◽  
Shou Qian Yuan ◽  
Tian Li Zhao
Keyword(s):  
Multilayer Structure ◽  
Optical Microscope ◽  
Alloy Layer ◽  
Mg Alloy ◽  
Micro Hardness ◽  
Roll Bonding ◽  
Fine Grained ◽  
Hardness Tester ◽  
Average Grain Size ◽  
Evolution Of Microstructure

In this paper, accumulative roll bonding (ARB) has been used to prepare the Al/Mg alloy multilayer structure composite materials with 1060Al sheet and MB2 sheet. The evolution of microstructure of the cladding materials during ARB processes was observed by optical microscope, scanning electron microscopy, and micro-hardness was measured by micro-hardness tester. The results show that a multilayer structure material of Al/Mg alloy with excellent bonding characteristics and fine grained microstructure was prepared by ARB processes. With the ARB cycles increasing, Mg alloy layer in multilayer composite material was necked and fractured, and the hardness of the Al and Mg alloy was increased. Average grain size was less than 1μm after ARB4 cycles.

Influence of Grain Size on Mechanical Properties in a Fe-9Ni-12Mn-2.5Si-1.0C TWIP Steel

2011 ◽  
Vol 197-198 ◽  
pp. 655-661
Author(s):  
Ze Bin Yang ◽  
Ding Yi Zhu ◽  
Wei Fa Yi ◽  
Shu Mei Lin ◽  
Cheng Mei Du
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Strain Hardening ◽  
Twip Steel ◽  
Optical Microscope ◽  
Coarse Grained ◽  
Microstructure Observation ◽  
Transmission Electron ◽  
Average Grain Size

We investigate the influence of grain size on mechanical properties in a Fe-9Ni-12Mn-2.5Si-1.0C TWIP steel by unidirectional tensile. Meanwhile the microstructures of the TWIP steel were observed and analyzed by optical microscope (OM) and transmission electron microscope (TEM). The experimental results show that the TWIP steel’s yield strength and tensile strength decrease with the increasing of grain size, whereas the plasticity increases with it. When the average grain size reaches to 27μm, the tensile strength is 1080MPa, the elongation percentage is 77%, and the strength-plasticity product achieves the 83160MPa•%. Steel’s strain hardening rate can be changed from three-stage to four-stage with the increasing of grain sizes, the areas of strain hardening by twin deformation mechanism are expanded. Through the microstructure observation we found that, coarse-grained TWIP steel conducts to twinning formation, the high density twins can increase the alloy’s ductility by splitting the grain.

Low Temperature Boronizing of Surface Nanostructured Ni-Cr-Mo Steel Using SMAT

2015 ◽  
Vol 830-831 ◽  
pp. 663-666 ◽  
Author(s):  
G. Sreejith ◽  
Teotia Sunny ◽  
J.N. Sahu ◽  
Chandrabalan Sasikumar
Keyword(s):  
Low Temperature ◽  
Defect Density ◽  
Thermochemical Treatment ◽  
Optical Microscope ◽  
Crystal Defects ◽  
Surface Mechanical Attrition Treatment ◽  
Metallic Surface ◽  
Hardness Tester ◽  
Nano Crystalline ◽  
Nanocrystalline Structures

Boronizing is a surface thermochemical treatment in which boron atoms are made to diffuse into a metallic surface at high temperatures. A nano-crystalline surface with larger defect density assists in enhancing the diffusion rate even at low temperatures. In the present work Ni-Cr-Mo steel is subjected to a surface mechanical attrition treatment (SMAT) to activate the surface with nanocrystalline structures and crystal defects. Subsequently the samples were boronized at low temperature regime (400°C - 600°C) for 5 hours using a pack boronizing technique. The microstructure, chemical analysis and hardness of borided layers were investigated using optical microscope, SEM – EDX and Microvicker’s Hardness Tester. The SMAT treated samples showed severe plastic deformation of the surface, nano-structured grains (10-30 nm) and larger defect density illustrating mechanically activated surface for diffusion. The boronizing had clearly demonstrated the diffusion of boron even at 400°C. The thickness of diffused layer was found to be about 20 µm at 400°C and 50 µm at 600°C for SMAT samples while the untreated samples showed practically no diffusion at 400°C and 12 µm at 600°C. The SEM-EDX results had confirmed the presence of boron at the diffused layer; however the hardness was found to be low. A maximum of 650 HV0.3was achieved by low temperature boronizing of SMAT treated samples.

Ultrasonic Surface Mechanical Attrition of Commercially Pure Ti to Induce Nanocrystalline Surface Layer

2010 ◽  
Vol 442 ◽  
pp. 152-157 ◽  
Author(s):  
M. Mansoor ◽  
J. Lu
Keyword(s):  
Pure Titanium ◽  
Nanocrystalline Structure ◽  
Surface Mechanical Attrition Treatment ◽  
X Ray Diffraction ◽  
Annealed Condition ◽  
X Ray ◽  
Commercially Pure ◽  
Transmission Electron ◽  
Mechanical Attrition ◽  
Xrd And Tem

In the domain of incremental nanotechnology, surface mechanical attrition treatment is a technique which can transform superficial structure of a material to nanocrystalline without changing the chemical composition. This study is a part of the development and implementation of the technique by using ultrasonic vibrations. The material used is pure titanium in rolled and annealed condition. The nanocrystalline structure is characterized using X-ray diffraction (XRD), and transmission electron microscopy (TEM). The measured grain size is in the order of 5~60 nm. A correlation in the results of XRD and TEM is also discussed.

Nanostructured 316 Stainless Steel Prepared under Traction by Surface Mechanical Attrition Treatment

2009 ◽  
Vol 614 ◽  
pp. 201-206
Author(s):  
Xiao Fang Yang ◽  
Jian Lu
Keyword(s):  
Stainless Steel ◽  
Optical Microscope ◽  
Steel Sample ◽  
Surface Mechanical Attrition Treatment ◽  
Stainless Steel Sample ◽  
Transmission Electron ◽  
Mechanical Attrition ◽  
Nanostructured Layer ◽  
Nanoindentation Measurement ◽  
Measurement Results

A nanostructured 316 austenitic stainless steel sample was prepared under traction using a new surface mechanical attrition treatment (SMAT) system. The microstructure of the surface layer of the SMATed sample was characterized using an optical microscope and transmission electron microscope (TEM). Microhardness on the cross-section was investigated by nanoindentation measurement. Results showed that a deeper nanostructured layer was obtained in comparison with that of the sample SMATed without traction.

Research on Mechanism of Surface Nanocrystalline Layer in 2219 Al Alloy Induced by Supersonic Fine Particles Bombarding

2016 ◽  
Vol 24 ◽  
pp. 1-8
Author(s):  
Yu Xiang Zhang ◽  
Jian Hai Yang ◽  
Li Ling Ge ◽  
Xin Zhang ◽  
Jia Zhao Chen
Keyword(s):  
Formation Mechanism ◽  
Fine Particles ◽  
Dislocation Cell ◽  
Grain Boundary Sliding ◽  
Al Alloy ◽  
Alloy Plate ◽  
Transmission Electron ◽  
Average Grain Size ◽  
Nanocrystalline Layer ◽  
Surface Nanocrystalline Layer

A nanostructured surface layer is formed on 2219 Al alloy plate by means of supersonic fine particles bombarding (SFPB). The surface microstructure formation mechanism of morphology change is systematically characterized by using scanning electron microscope (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The average grain size of 30nanostructured layer is about 30 nm when the surface of sample is induced by severe plastic deformation. Based on the experimental observations, nanoscale dislocation cells exist in strain layer about 200 from the surface, and we put forward a new formation mechanism of Al alloy surface nanocrystalline layer through theoretical analysis. The original grain is segmented fast into nanoscale dislocation cell or lamellar cell. As the Burgers vector of cell walls continue to accumulate, grain orientation difference constantly increases to form the nanoscale subboundary. Eventually, equiaxed nanocrystallites with random crystallographic orientations are formed by grain rotating or grain boundary sliding.

Assessment of Mechanical Properties and Transformation Behavior of Locally-Made Ni-Ti Alloys Used in Orthodontics

2008 ◽  
Vol 55-57 ◽  
pp. 245-248 ◽  
Author(s):  
Nattiree Chiranavanit ◽  
Anak Khantachawana ◽  
N. Anuwongnukroh ◽  
Surachai Dechkunakorn
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Testing Machine ◽  
Optical Microscope ◽  
Treatment Temperature ◽  
Bending Test ◽  
Hardness Tester ◽  
Ti Alloys ◽  
Heat Treated ◽  
Average Grain Size

Ni-Ti alloy wires have been widely used in clinical orthodontics because of their properties of superelasticity (SE) and shape memory effect (SME). The purpose of this study was to assess the mechanical properties and phase transformation of 50.7Ni-49.3 Ti (at%) alloy (NT) and 45.2Ni-49.8Ti-5.0Cu (at%) alloy (NTC), cold-rolled with various percent reductions. To investigate SE and SME, heat-treatment was performed at 400°C and 600°C for 1 h. The specimens were examined using an Energy-Dispersive X-ray Spectroscope (EDS), Differential Scanning Calorimeter (DSC), Universal Testing Machine (Instron), Vickers Hardness Tester and Optical Microscope (OM). On the three-point bending test, the superelastic load-deflection curve was seen in NTC heat-treated at 400°C. Furthermore, NT heat-treated at 400°C with 30% reduction produced a partial superelastic curve. For SME, no conditions revealed superelasticity at the oral temperature. Micro-hardness value increased with greater percentage reduction. The average grain size for all specimens was typically 55-80 µm. The results showed that locally-made Ni-Ti alloys have various transformation behaviors and mechanical properties depending on three principal factors: chemical composition, work-hardening (the percent reduction) and heat-treatment temperature.

Study on the Structure and Properties of Surface Nanocrystallized Zr-4

2011 ◽  
Vol 415-417 ◽  
pp. 660-665
Author(s):  
Cong Hui Zhang ◽  
Da Li Liu ◽  
Xin Zhe Lan ◽  
Xi Cheng Zhao
Keyword(s):  
Surface Roughness ◽  
Surface Layer ◽  
Processing Time ◽  
Optical Microscope ◽  
Surface Mechanical Attrition Treatment ◽  
Structure And Properties ◽  
Nanostructured Surface ◽  
Grain Sizes ◽  
Mechanical Attrition ◽  
Average Grain Size

A nanostructured surface layer was obtained on the surface of Zr-4 by surface mechanical attrition treatment(SMAT). The structure and the properties of the SMAT sample were analyzed by means of the optical microscope, hardness and polarization curve testing. The results show that， when processing time for 5min, the average grain sizes on the surface layer can be refined to 23nm. The average grain size by SMAT-ed for 15min is 20nm, which is the smallest. The microhardness have a significant increase, the surface roughness also increase, and the corrosion resistance reduce in 1mol H2SO4solution.

Surface Nanocrystallization of Zircaloy-4 by Surface Mechanical Attrition Treatment

2010 ◽  
Vol 658 ◽  
pp. 452-455 ◽  
Author(s):  
Cong Hui Zhang ◽  
Xiao Ge Duan ◽  
Lian Zhou ◽  
Xin Zhe Lan
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Grain Size ◽  
Surface Hardness ◽  
Surface Mechanical Attrition Treatment ◽  
Dislocation Slip ◽  
Transmission Electron ◽  
Mechanical Attrition ◽  
Average Grain Size ◽  
Mechanical Twins

A nanostructured surface layer was induced on zircaloy-4 by the method of surface mechanical attrition treatment (SMAT). X-ray diffraction and microhardness tester were applied to identify the average grain size and hardness of specimen processed for different duration, transmission electron microscopy and high-resolution transmission electron microscopy were adopted to observe the microstructure of specimen. The results showed that the surface hardness enhanced gradually and then stabilized with the processing duration increasing, while the average grain size declined gradually, to the minimum 20 nm at 15 min, then increased. The formation of nanocrystalline was due to the mechanical twins and dislocation slip.

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