Effect of Surface Nano-Crystallization on Microstructure and Mechanic Properties of Commercial Pure Titanium

2004 ◽  
Vol 261-263 ◽  
pp. 1605-1610 ◽  
Author(s):  
Ai Ling Wen ◽  
R.M. Ren ◽  
Sheng Wu Wang ◽  
Shinichi Nishida
Keyword(s):  
Grain Size ◽  
Surface Layer ◽  
Shot Peening ◽  
Pure Titanium ◽  
High Energy ◽  
X Ray Diffraction ◽  
Surface Microhardness ◽  
Commercial Pure Titanium ◽  
Nano Crystalline ◽  
Crystalline Surface

The paper investigated nano-crystallization on surface layer of commercial pure titanium by using high-energy shot peening. The grain size and the microstructure in deformed surface layer by high-energy shot peening are analyzed with X-ray diffraction and TEM etc. In addition, the variations of surface microhardness are examined after high-energy shot peening. The results described that the nano-crystalline surface layer have been formed in commercial pure titanium with a structure of hexagonal closet packet, by high-energy shot peening. The surface microhardness increases and the grain size in nano-crystalline surface layer diminishes, with increasing the time in high-energy shot peening. The minimum nano-crystalline grain size is approximately 40 nm.

High Energy Shot Peening of Commercially Pure Titanium TIG Weld Joint

2010 ◽  
Vol 148-149 ◽  
pp. 659-663
Author(s):  
Chun Huan Chen ◽  
Rui Ming Ren
Keyword(s):  
Surface Layer ◽  
Weld Joint ◽  
Shot Peening ◽  
Welded Joint ◽  
Pure Titanium ◽  
High Energy ◽  
Commercially Pure Titanium ◽  
Nanostructured Surface ◽  
Commercially Pure ◽  
Cp Ti

Commercially pure Titanium (CP-Ti) TIG weld joint was treated by means of high energy shot peening (HESP) using a shot peening equipment commonly used in industry. The nanostructured surface layer was characterized by XRD, TEM, SEM and Microhardometer. The results showed that surface nanocrystallization of CP-Ti TIG weld joint were realized by high energy shot peening treatment. The finest grain size in the top surface layer is about 40nm. The hardness of the surface layer is enhanced significantly after shot peening compared with that of the as-welded joint, which resulted in a remarkable surface hardening effect. Surface welded defects such as air pores are eliminated successfully so that relative uniform surface layer was obtained.

Effect of Surface Nanocrystallization Method on Fatigue Strength of TA2

2009 ◽  
Vol 620-622 ◽  
pp. 545-549 ◽  
Author(s):  
Ai Ling Wen ◽  
Rui Ming Ren ◽  
Sheng Wu Wang ◽  
Jun Yong Yang
Keyword(s):  
Fatigue Strength ◽  
Fatigue Limit ◽  
Shot Peening ◽  
Fatigue Crack Initiation ◽  
Pure Titanium ◽  
Small Diameter ◽  
Surface States ◽  
High Energy ◽  
Commercial Pure Titanium ◽  
Initiation And Propagation

The enhancement of the fatigue strength is significant for the engineering applications of commercial pure titanium and its alloys. The paper investigated improvement of fatigue strength for commercial pure titanium by combined high-energy shot peening. Firstly, nano-crystallization in surface layer of pure titanium was carried out by high-energy shot peening, and then the shot peening with small diameter shots was introduced to degrade the surface roughness, enhancing the quality of the nano-grained surface. The fatigue limit of pure titanium by high-energy shot peening turns out to be increased by 34%, and the fatigue limit of pure titanium by compound high-energy shot peening turns out to be increased by 52.3%, according to the results. Effective factors such as surface states etc. to fatigue life, the fatigue crack initiation and propagation behaviors were also discussed in this paper.

Effect of Nitridation Magnetic Properties of Nanocrystalline Fe-Co Alloy Powders

2010 ◽  
Vol 654-656 ◽  
pp. 1106-1109
Author(s):  
Ya Qiong He ◽  
Chang Hui Mao ◽  
Jian Yang
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Alloy Powder ◽  
High Energy ◽  
X Ray Diffraction ◽  
Powder Mixtures ◽  
X Ray ◽  
Transmission Electron ◽  
Nitridation Temperature ◽  
Microstructure And Magnetic Properties

Nanocrystalline Fe-Co alloy powders, which were prepared by high-energy mechanical milling, were nitrided under the mixing gas of NH3/H2 in the temperature range from 380°C to 510°C. X-ray diffraction (XRD) was used to analyze the grain size and reaction during the processing. The magnetic properties of the nitrided powders were measured by Vibrating Sample Magnetometer (VSM). The results show that with the appearance of Fe4N phase after nitride treatment, and the grain-size of FeCo phase decreases with the increase of nitridation temperature between 380°C to 450°C.The saturation magnetization of nitrided alloy powder treated at 480°C is about 18% higher than that of the initial Fe-Co alloy powder, accompanied by the reduction of the coercivity. Transmission electron microscope (TEM) was used, attempting to further analyze the effect of Fe4N phase on microstructure and magnetic properties of the powder mixtures.

Low carbon steel with nanostructured surface layer induced by high-energy shot peening

2001 ◽  
Vol 44 (8-9) ◽  
pp. 1791-1795 ◽  
Author(s):  
G Liu ◽  
S.C Wang ◽  
X.F Lou ◽  
J Lu ◽  
K Lu
Keyword(s):  
Surface Layer ◽  
Carbon Steel ◽  
Shot Peening ◽  
Low Carbon Steel ◽  
High Energy ◽  
Low Carbon ◽  
Nanostructured Surface

Effect of Pre-Shot Peening on Plasma Nitriding Kinetics of Austenitic Stainless Steel

2013 ◽  
Vol 634-638 ◽  
pp. 2955-2959 ◽  
Author(s):  
Lie Shen ◽  
Liang Wang ◽  
Jiu Jun Xu ◽  
Ying Chun Shan
Keyword(s):  
Stainless Steel ◽  
Surface Layer ◽  
Austenitic Stainless Steel ◽  
Shot Peening ◽  
Plasma Nitriding ◽  
Nitrogen Diffusion ◽  
X Ray Diffraction ◽  
304 Austenitic Stainless Steel ◽  
Strain Induced Martensite ◽  
Kinetics Of

The fine grains and strain-induced martensite were fabricated in the surface layer of AISI 304 austenitic stainless steel by shot peening treatment. The shot peening effects on the microstructure evolution and nitrogen diffusion kinetics in the plasma nitriding process were investigated by optical microscopy and X-ray diffraction. The results indicated that when nitriding treatments carried out at 450°C for times ranging from 0 to 36h, the strain-induced martensite transformed to supersaturated nitrogen solid solution (expanded austenite), and slip bands and grain boundaries induced by shot peening in the surface layer lowered the activation energy for nitrogen diffusion and evidently enhanced the nitriding efficiency of austenitic stainless steel.

SYNTHESIS OF NANO-CRYSTALLINE Cu-Cr ALLOY BY MECHANICAL ALLOYING

2012 ◽  
Vol 05 ◽  
pp. 496-501 ◽  
Author(s):  
S. SHEIBANI ◽  
S. HESHMATI-MANESH ◽  
A. ATAIE
Keyword(s):  
Mechanical Alloying ◽  
Structural Evolution ◽  
High Energy ◽  
Lattice Parameter ◽  
Control Agent ◽  
Milling Process ◽  
X Ray Diffraction ◽  
Nano Crystalline ◽  
High Energy Ball Mill ◽  
Energy Ball

In this paper, the influence of toluene as the process control agent (PCA) and pre-milling on the extension of solid solubility of 7 wt.% Cr in Cu by mechanical alloying in a high energy ball mill was investigated. The structural evolution and microstructure were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques, respectively. The solid solution formation at different conditions was analyzed by copper lattice parameter change during the milling process. It was found that both the presence of PCA and pre-milling of Cr powder lead to faster dissolution of Cr . The mean crystallite size was also calculated and showed to be about 10 nm after 80 hours of milling.

Appropriate Conditions for Preparation of Nanosized WO3 through High-Energy-Milling

2011 ◽  
Vol 194-196 ◽  
pp. 665-668
Author(s):  
Chun Huan Chen ◽  
Rui Ming Ren
Keyword(s):  
Grain Size ◽  
Milling Time ◽  
Rotation Speed ◽  
Processing Parameters ◽  
High Energy ◽  
Charge Ratio ◽  
Activation Process ◽  
X Ray Diffraction ◽  
High Energy Milling ◽  
Transmission Electron

In order to synthesize WC-Co nanopowders through an integrated mechanical and thermal activation process, WO3-Co2O3-C nanopowders need to be obtained first. It is critical how to obtain the WO3-Co2O3-C nanopowders efficiently. The effect of processing parameters on the grain size during high-energy-milling of WO3-Co2O3-C mixed powders was studied via X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results show that the grain size of reactants can be effectively decreased with increasing the milling time, rotation speed, and charge ratio. After a certain time milling, both WO3 and C powders achieve nano-level in grain size and mixed homogeneously. The appropriate milling parameters for fabricating nanosized WO3+C+Co2O3 powders are suggested to be 4 to 8 hours of milling time, 400 RPM of rotation speed, and 40:1 to 60:1 of charge ratio.

The Effect of Strain Rate on the Plastic Deformation Mode of CP-Ti during Surface Nanocrystallization

2011 ◽  
Vol 675-677 ◽  
pp. 239-242
Author(s):  
Chun Huan Chen ◽  
Cheng Jin ◽  
Rui Ming Ren
Keyword(s):  
Plastic Deformation ◽  
Surface Layer ◽  
Strain Rate ◽  
Shot Peening ◽  
Pure Titanium ◽  
Deformation Mode ◽  
Rate Variation ◽  
Commercially Pure Titanium ◽  
Surface Nanocrystallization ◽  
Cp Ti

The effect of the strain rate on the surface nanocrystallization of titanium is investigated both theoretically and experimentally in this paper. The strain rate variation and stress distribution from surface to the interior of titanium during shot peening are estimated firstly using finite element method. Then shot peening experiment is carried out on a commercially pure titanium (CP-Ti) plate, and the obtained surface microstructures is characterized by transmission electron microscopy (TEM). Combining theoretical simulations and experimental observations, the effect of strain rate on the strain accommodation mechanism and plastic deformation mode are discussed. It is concluded that the strain rate and stress achieve the highest at the top surface layer of CP-Ti, and the strain rate decrease dramatically from the surface to the interior. The strain rate at the top surface layer is up to 104 s-1, which leads to superplastic deformation of Ti. There is no mechanical twin in the surface layer, instead, deformation lamella and adiabatic shear bands are the dominating microstructures. By means of rotation recrystallization, those deformation bands evolve to nanocrystallines.

Influences of Surface Nanocrystallization Induced by High-Energy Spot Peening on Microstructure and Properties of Magnesium Alloy

2013 ◽  
Vol 690-693 ◽  
pp. 2120-2125 ◽  
Author(s):  
Li Wen Tang ◽  
Jian Sun ◽  
Jin Zhang ◽  
Xin Bing Ou ◽  
Zhi Ming Zhou
Keyword(s):  
Surface Layer ◽  
Magnesium Alloys ◽  
Corrosion Potential ◽  
Electrochemical Measurement ◽  
Corrosion Current ◽  
High Energy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface Nanocrystallization ◽  
Grain Sizes

As relatively new structure materials, magnesium and its alloys demonstrated significant potential for applications in many industries. However, magnesium alloys were easy to be corroded which greatly limited their development. AZ31B and AZ91D, two widely used commercial magnesium alloys in various industries, were chosen to be produced nanostructure on the surface layer, called Surface Nanocrystallization (SNC) by High Energy Spot Peening (HESP). The microstructure was characterized by Scan Electronic Microscopy (SEM) and X-ray diffraction (XRD) in this paper. Microhardness and corrosion resistance were measured by microhardness tester and electrochemical measurement system respectively. Experimental results showed that after HESP the grain sizes in the surface layer were obviously reduced into nanoscale; microhardness was greatly increased in the treated surface, about two times as much as that of original and corrosion current density in polarization curve was evidently raised while corrosion potential changed little.

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