scholarly journals Nanoindentation Properties of 18CrNiMo7-6 Steel after Carburizing and Quenching Determined by Continuous Stiffness Measurement Method

Metals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 125 ◽  
Author(s):  
Guiyuan Zhou ◽  
Jian Guo ◽  
Junyu Zhao ◽  
Qian Tang ◽  
Zhaonan Hu
Keyword(s):  
Yield Strength ◽  
Indentation Depth ◽  
Contact Stiffness ◽  
Case Hardening ◽  
Modified Model ◽  
Cutoff Parameter ◽  
Modified Layer ◽  
Continuous Stiffness Measurement ◽  
Surface Modified ◽  
Insight Into

In this work, the nanomechanical properties involving the indentation size effect (ISE) and yield strength of a surface-modified layer of 18CrNiMo7-6 steel after case hardening were investigated via nanoindentation experiments. The experimental results showed that the hardness increased with an increase in strain rate; the contact stiffness versus indentation depth curves take the form of upper convexity due to residual compressive stress relaxation. On the basis of the Ruiz-Moreno model, a modified model considering the cutoff parameter as a function of indentation depth was proposed. This model was able to better describe the ISE of the surface-modified layer. With the Hough transform error angle of 0.1° as the critical value (h0.1° is the corresponding depth), when h > h0.1°, the yield strength calculated by the Ma model started to disperse at the depth of h0.1°. These results provide useful insight into the local mechanical properties of 18CrNiMo7-6 steel after carburizing and quenching treatment.

Corrosion Behaviours of Mo Modified Ti6Al4V Alloy in Hank’s Solution

2009 ◽  
Vol 610-613 ◽  
pp. 1150-1154
Author(s):  
Ai Lan Fan ◽  
Cheng Gang Zhi ◽  
Lin Hai Tian ◽  
Lin Qin ◽  
Bin Tang
Keyword(s):  
Electrochemical Corrosion ◽  
Optical Emission ◽  
Ti6al4v Alloy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffusion Layers ◽  
Modified Layer ◽  
Surface Modified ◽  
Hank’S Solution ◽  
And Diffusion

The Mo surface modified layer on Ti6Al4V alloy was obtained by the plasma surface alloying technique. The structure and composition of the Mo modified Ti6Al4V alloy was investigated by X-ray diffraction (XRD) and glow discharge optical emission spectroscopy (GDOES). The Mo modified layer contains Mo coating on subsurface and diffusion layers between the subsurface and substrate. The X- ray diffraction analysis of the Mo modified Ti6Al4V alloy reveals that the outmost surface of the Mo modified Ti6Al4V alloy is composed of pure Mo. The electrochemical corrosion performance of the Mo modified Ti6Al4V alloy in 25°C Hank’s solution was investigated and compared with that of Ti6Al4V alloy. Results indicate that the self-corroding electric potential and the corrosion-rate of the Mo modified Ti6Al4V alloy are higher than that of Ti6Al4V alloy in 25°C Hank’s solution.

Nonlinear effect of tooth-slot transition on axial vibration, contact state and speed fluctuation in traveling wave ultrasonic motor

2017 ◽  
Vol 232 (19) ◽  
pp. 3424-3438 ◽  
Author(s):  
Dongsheng Zhang ◽  
Shiyu Wang
Keyword(s):  
Traveling Wave ◽  
Contact Stiffness ◽  
Nonlinear Phenomena ◽  
Axial Vibration ◽  
Contact State ◽  
State Response ◽  
Nonlinear Contact ◽  
Speed Fluctuation ◽  
Transition Force ◽  
Insight Into

The tooth-slot transition creates an axial excitation on traveling wave ultrasonic motors. It induces a rotor’s axial rigid vibration, which in turn affects the contact state and arouses speed fluctuation. To gain an insight into this problem, this work examines the relationships between the tooth-slot transition, axial vibration, nonlinear contact, and speed fluctuation. An analytical model governing rotor’s vibration is developed, where the transition force, nonlinear contact stiffness, and pre-pressure are included. The contact stiffness is demonstrated to decrease with an increase in stator’s vibration amplitude and it is approximated by polynomial fitting such that the nonlinear problem can be analytically solved. The primary, 1/2 subharmonic, and 2/1 superharmonic resonances are analyzed to determine the amplitude–frequency response and steady-state response. Nonlinear phenomena regarding the three types of resonances are identified. The interaction between the transition force, axial vibration, contact stiffness and speed fluctuation is investigated through a new contact model. The results imply that the rotor vibration induces rotating acceleration and leads to speed fluctuation. In addition, the rotor speed fluctuates in a similar fashion with the axial vibration.

On the Measurement of Creep by Nanoindentation with Continuous Stiffness Techniques

2004 ◽  
Vol 841 ◽  
Author(s):  
Andrei Rar ◽  
Sangjoon Sohn ◽  
Warren C. Oliver ◽  
David L. Goldsby ◽  
Terry E. Tullis ◽  
...  
Keyword(s):  
Time Dependence ◽  
Contact Area ◽  
Indentation Depth ◽  
Contact Stiffness ◽  
Point Of View ◽  
Hard Material ◽  
Thermal Drift ◽  
Material Creep ◽  
Creep Measurements ◽  
Using Data

ABSTRACTMeasurement of material creep parameters by means of nanoindentation using continuous stiffness techniques avoids the problems associated with thermal drift that often plague creep measurements based on the time dependence of the indentation depth alone [1, 2]. Problems with thermal drift are negligible from a practical point of view during continuous stiffness measurements because the contact stiffness can be measured over a short time period, typically less than one second, during which time the displacements due to thermal drift are minimal. Determination of the time dependence of the indentation depth from the stiffness data relies on the well-known relation between contact stiffness and the square root of the contact area. For pyramidal indenters, the true indentation contact depth must be proportional to the contact stiffness, leading to the assumption that indentation depth is also proportional to the contact stiffness. In this study, we critically examine this assumption using data obtained from experiments on a relatively soft material, epoxy, and a relatively hard material, fused quartz. The results show that just after initial load application, the change in contact area may be different than that expected from the change in indentation depth. One possible explanation for the observed behavior is examined by finite element modeling.

Research of Electrolytic-Plasma Carbonitriding and Nitriding Influence on Phase Composition of the Stainless Steel

2013 ◽  
Vol 404 ◽  
pp. 40-43
Author(s):  
Маzhyn Skakov ◽  
Sherzod Kurbanbekov ◽  
Almira Zhilkаshinova
Keyword(s):  
Stainless Steel ◽  
Phase Composition ◽  
Austenitic Steel ◽  
Phase Structure ◽  
Plasma Processing ◽  
High Hardness ◽  
Residual Austenite ◽  
Nitride Phase ◽  
Modified Layer ◽  
Surface Modified

In the present work we have studied the phase structure of surface modified layer of austenitic steel 12Cr18Ni10Ti after electrolytic-plasma carbonitriding and nitriding. It was determined that the carbonitriding and nitriding with the subsequent hardening formed carbide and nitride phase. Also it is revealed that steel 12Cr18Ni10Ti after the electrolyte-plasma processing has high hardness. The microstructure of samples surface is presented by martensite and residual austenite. Optimum modes of steel 12Cr18Ni10Ti carbonitriding and nitriding by electrolytic-plasma way have been identified.

Structural-Phase Transformations in R6m5 Steel while Electrolytic-Plasma Processing

2014 ◽  
Vol 904 ◽  
pp. 217-221 ◽  
Author(s):  
Маzhyn Skakov ◽  
Erlan Batyrbekov ◽  
Bauyrzhan Rakhadilov ◽  
Michael Scheffler
Keyword(s):  
High Speed ◽  
Structural Phase ◽  
Plasma Processing ◽  
High Speed Steel ◽  
R6m5 Steel ◽  
Electrolytic Plasma Processing ◽  
Modified Layer ◽  
Surface Modified ◽  
Structural Phase Transformations ◽  
Surface Changes

The article examines regularities of high-speed steel surface changes in the phase and structural states of during the electrolytic-plasma processing. It is determined that after modification by electrolytic-plasma influence on the surface of R6M5 high-speed steel formation of small pores, microdefects and fine inclusion. Surface modified layer consists of nitrogen austenite, nitrogen martensite and fine nitride particles.

Surface Modification of High-Speed Steel by Plasma Nitriding

2014 ◽  
Vol 709 ◽  
pp. 403-409 ◽  
Author(s):  
Bauyrzhan K. Rakhadilov ◽  
Mazhyn Skakov ◽  
Erlan Batyrbekov ◽  
Michael Scheffler
Keyword(s):  
Surface Layer ◽  
Phase Composition ◽  
Diffusion Layer ◽  
High Speed ◽  
Steel Surface ◽  
Plasma Nitriding ◽  
High Speed Steel ◽  
R6m5 Steel ◽  
Modified Layer ◽  
Surface Modified

The article investigates the changing in the structure and phase composition of the R6M5 high-speed steel surface layer after electrolytic-plasma nitriding. It is found that after electrolytic-plasma nitriding on the R6M5 steel surface, modified layer is formed, which consist from a diffusion layer. It was showed phase composition of difysion layer is changing depending on the nitriding. It is found that electrolytic-plasma nitriding lead to accelerated formation of the modified layer. It is determined that after electrolytic-plasma nitriding on the high-speed steel surface, modified layer is formed, consisting only of the diffusion layer.

UNDERWATER SLIDING PROPERTIES: EFFECT OF SLIDER SHAPE AND SURFACE WETTABILITY

2016 ◽  
Vol 23 (05) ◽  
pp. 1650042 ◽  
Author(s):  
A. KIRVESLAHTI ◽  
K. MIELONEN ◽  
K. IKONEN ◽  
W. CUI ◽  
M. SUVANTO ◽  
...  
Keyword(s):  
Contact Angle ◽  
Surface Properties ◽  
Dynamic Test ◽  
Test Method ◽  
Surface Wettability ◽  
Flow Conditions ◽  
Modified Model ◽  
Variable Flow ◽  
Developed Surface ◽  
Surface Modified

A dynamic test method for the measurement of the underwater sliding properties of model boats has been developed. Surface-modified model boats were examined to assess how the surface wettability properties affect sliding. Along with the surface properties, the influence of the boat shape was considered. We studied various coatings in the contact angle range of 3–162[Formula: see text] with two model boat shapes. The hydrophobicity of the surfaces influenced the sliding speed of the model boat depending on the boat shape. The method is applicable to study sliding properties of model boats with different surfaces in variable flow conditions.

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