Surface layer modification by cryogenic burnishing of Al 7050-T7451 alloy with near ultra-fine grained structure

2021 ◽  
pp. 1-22
Author(s):  
Bo Huang ◽  
Yusuf Kaynak ◽  
Ying Sun ◽  
Marwan Khraisheh ◽  
I. S. Jawahir
Keyword(s):  
Surface Integrity ◽  
Surface Hardness ◽  
Grain Structure ◽  
Fine Grained ◽  
Compressive Stresses ◽  
Wear And Corrosion ◽  
Cryogenic Burnishing ◽  
Subsurface Layers ◽  
Fine Grained Structure ◽  
Wear And Corrosion Resistance

Abstract Burnishing has been increasingly utilized to improve the surface integrity of manufactured components. The generation of surface and subsurface layers with ultrafine grains, attributed to severe plastic deformation and dynamic recrystallization, leads to improved surface integrity characteristics including surface and subsurface hardness and reduction in surface roughness. Additionally, due to the generation of compressive stresses within the refined layers, increase in fatigue life and improved wear and corrosion resistance can be achieved. In this study, we apply cryogenic burnishing on Al 7050-T7451 discs and compare the surface integrity characteristics with dry conventional burnishing. A special roller burnishing tool with flexible rotating roller head was designed and used to perform the cryogenic burnishing experiments using liquid nitrogen as the coolant. The results show that cryogenic burnishing can increase the surface hardness by an average of 20-30% within a layer depth of 200 μm compared to only 5-10% increase using dry conventional burnishing. Refined layers with nano grain structure were also generated. During cryogenic burnishing the tangential burnishing forces were higher than those of dry conventional burnishing due to rapid cooling and work hardening of the material.

Hard, Wear Resistant Metal Surfaces for Industrial Applications through Laser Powder Deposition

2007 ◽  
Vol 534-536 ◽  
pp. 1537-1540 ◽  
Author(s):  
James Sears ◽  
Aaron Costello
Keyword(s):  
Surface Hardness ◽  
Base Material ◽  
Surface Modifications ◽  
Industrial Applications ◽  
Wear Testing ◽  
Hard Material ◽  
Laser Powder Deposition ◽  
Wear And Corrosion ◽  
Powder Deposition ◽  
Wear And Corrosion Resistance

Most materials produced today are monolithic structures that are heat treated to perform a particular function. Laser Powder Deposition (LPD) is a technology capable of modifying a metallic structure by adding the appropriate material to perform a desired function (e.g., wear and corrosion resistance). LPD offers a unique fabrication technique that allows the use of soft (tough) materials as base structures. Through LPD a hard material can be applied to the base material with little thermal input (minimal dilution and heat-affected-zone {HAZ}), thus providing the function of a heat treatment or other surface modifications (e.g., carburizing, nitriding, thermal spray and electroplating). Several materials (e.g., Stellite 6 &21, 316 SS, 420 SS, M4, Rex 20, Rex 121, 10V, AeroMet 100, CCW+, IN 625 and IN 718) have been deposited on to carbon steel (4140, 4340, 1566, 1018) substrates to provide various functions for a number of industrial applications. These surface modifications have been evaluated through standard wear testing (ASTM G-65), surface hardness (Rc), micro-hardness (vickers), and optical microscopy. The results from these evaluations will be presented along with several industrial application case studies.

Thermoelectric properties of germanium telluride with fine-grained structure

2020 ◽  
Vol 11 ◽  
pp. 15-25
Author(s):  
L. D. Ivanova ◽  
◽  
Yu. V. Granatkina ◽  
I. Yu. Nikhezina ◽  
A. G. Malchev ◽  
...  
Keyword(s):  
Thermoelectric Properties ◽  
Melt Spinning ◽  
High Energy ◽  
Grain Structure ◽  
Thermoelectric Efficiency ◽  
Fine Grained ◽  
Germanium Telluride ◽  
Fine Grained Structure ◽  
Properties Of Materials ◽  
P Type

The microstructure and thermoelectric properties of materials based on germanium telluride p-type conductivity doped with copper and bismuth obtained by hot pressing of three types powders prepared by grinding an ingot to a size of hundreds microns (0.315  mm) to hundreds of nanometers (mechanical activation) in planetary high-energy mill and melt spinning were investigated. The microstructure of the samples were analyzed by optical and electron scanning microscopies. The nanoscale grain structure of these samples was established. The thermoelectric characteristics of the materials: Seebeck coefficient, electrical and thermal conductivities, were measured both at room temperature and in the temperature range of 100 – 800 K. The slopes of these dependencies are estimated. The coefficient of thermoelectric figure of merit is calculated. The higher thermoelectric efficiency (ZT = 1.5 at 600 K) was received for the samples hot-pressed from granules, prepared by melt spinning.

Grain Structure and Precipitates in Squeeze Casting Al-Li-Mg-Zr Alloy

2014 ◽  
Vol 887-888 ◽  
pp. 329-332
Author(s):  
Li Fan ◽  
Zhong Wei Chen ◽  
Qi Tang Hao
Keyword(s):  
Grain Boundaries ◽  
Squeeze Casting ◽  
Grain Structure ◽  
Fine Grained ◽  
Fine Grain ◽  
The Matrix ◽  
Fine Grained Structure ◽  
Heat Treated Condition ◽  
Micrometer Size ◽  
Zr Alloy

Grain structure and precipitates in squeeze casting Al-Li-Mg-Zr alloy for aircraft industry were investigated in heat treated condition, using X-ray diffraction, optical microscopy and transmission electron microscopy. An ultra fine grained structure in sub-micrometer size was obtained, having fine nanograins in it with polycrystalline diffraction rings that are different from the single-crystal patterns in the matrix. Ultra fine grain areas are generally located on the grain boundaries and sub-grain boundaries. In addition, TEM observations indicates the presence of lenticular δ' (Al3Li) phases that symmetrical distributed around the GP zones. The alloy also contains spherical β' (Al3Zr) dispersoids, and S1 (Al2MgLi) phases.

Grain Refinement of 6061 Al Alloy by the Modified Strain-Induced Melt- Activated(SIMA) Process for Semi-Solid Processing

2007 ◽  
Vol 119 ◽  
pp. 311-314 ◽  
Author(s):  
Young Buem Song ◽  
Chun Pyo Hong
Keyword(s):  
Grain Refinement ◽  
Grain Structure ◽  
Al Alloy ◽  
Fine Grained ◽  
Fine Grain ◽  
Fine Grained Structure ◽  
Size Uniformity ◽  
Sima Process ◽  
Semi Solid ◽  
6061 Al Alloy

The dynamic process of fine grain evolution of 6061 aluminum alloy during modified strain-induced, melt-activated (SIMA) process was studied. The modified SIMA process employed casting, two stage homogenization, warm multi-forging, and recrystallization and partial melting (RAP). Multi-forging was carried out at a strain rate of 9x10-3 s-1 to accumulate high strains, with decreasing temperature from 250 to 200 °C. The alloy multi-forged with the accumulated strain of about 12 and RAP at 640 °C for 10 min exhibited the uniform equiaxed recrystallized grain structure. Accordingly, it was evident that multi-forging was very effective on grain refinement and grain size uniformity. The present modified SIMA process was discussed as an alternative thermo-mechanical processing for preparing the alloys with fine grained structure for semi solid processing.

Plasma Nitriding of Deep Narrow Cavities

2011 ◽  
Vol 465 ◽  
pp. 267-270 ◽  
Author(s):  
Z. Pokorný ◽  
Vojtěch Hruby
Keyword(s):  
Corrosion Resistance ◽  
Fatigue Strength ◽  
Penetration Depth ◽  
Plasma Nitriding ◽  
Surface Hardness ◽  
Nitrided Steel ◽  
New Information ◽  
Wear And Corrosion ◽  
Wear And Corrosion Resistance

Technology of plasma nitriding is widely used to increase the surface hardness, fatigue strength, wear and corrosion resistance of steels [1, 2]. In this study, the properties of plasma nitrided steel of various diameters at various pressures are investigated. There was obtained new information about possibilities of plasma nitriding technology and its applications to the cavities with diameters of 6, 8 and 10 mm and a penetration depth of 400 mm.

scholarly journals Effect of Microstructure and Mechanical Properties of Al5083 Alloy Processed by ECAP at Room Temperature and High Temperature

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 683
Author(s):  
Muneer Baig ◽  
Ateekh Ur Rehman ◽  
Jabair A. Mohammed ◽  
Asiful H. Seikh
Keyword(s):  
Equal Channel Angular Pressing ◽  
Room Temperature ◽  
Optical Microscope ◽  
Grain Structure ◽  
Fine Grained ◽  
Angular Pressing ◽  
Al 5083 Alloy ◽  
Fine Grained Structure ◽  
Number Of Passes

In this investigation, the focus is on improving the quality of the Al 5083 alloy by equal-channel angular pressing (ECAP) innovation. Equal-channel angular pressing (ECAP) is one of the best technologies for converting macro grain into ultra-fine-grained structure. Grain structure which is finer increases the strength of the material. In this work, a severe plastic deformation using equal-channel angular pressing (ECAP) up to 3 passes was given on Al5083 alloy using path BC at room temperature. The evolution of the microstructure was studied using an optical microscope. Tensile studies were also done. Both hardness (Vickers) and tensile strength rises as the number of passes increases; however, the ductility or the percentage of elongation increases. It can be said that the final product of this aforementioned alloy after ECAPed processing is considered to be suitable for various applications in which higher strength is required.

Surface Modification of Pure Titanium by Nitrogen Ion Implantation at Different Beam Energy and Dose

2011 ◽  
Vol 462-463 ◽  
pp. 750-755 ◽  
Author(s):  
Nurdin Ali ◽  
Haryanti Samekto ◽  
Mohd Imran Ghazali ◽  
M. Ridha
Keyword(s):  
Corrosion Resistance ◽  
Pure Titanium ◽  
Surface Hardness ◽  
Surface Characteristics ◽  
Grazing Incidence ◽  
Near Surface ◽  
Wear And Corrosion ◽  
Nitrogen Ions ◽  
Nitrogen Ion ◽  
Wear And Corrosion Resistance

The implantation of nitrogen ion is one of the important techniques for modifying the surface characteristics to improve wear and corrosion resistance of commercially pure (cp) Titanium. Although nitrogen ions implanted titanium in various dose demonstrated significant changes of the wear and corrosion resistance, the variable energy implanted is still not yet fully studied. Nitrogen ions were implanted in cp Titanium surface with varies of both dose of 0.5; 1.0 and 2.0 x1017 ions cm-2 and energy of 80, 100 and 115 keV. The nitrogen ion implanted cp Titanium demonstrated an increase in the surface hardness and improvement in corrosion behavior. The maximum surface hardness was delivered by the specimens implanted with the dose of 2.0x1017 ions cm-2 at energy of 80 keV. Grazing incidence x-ray diffraction studies indicated that TiN phase was formed on near surface substrate. Electrochemical tests in 3.5%-wt NaCl solution depicted significant improvements in corrosion resistance for specimens implanted with dose of 0.5x1017 and 1.0x1017 ions cm-2 at energy of 80 keV, dose of 1.0x1017 and 2.0x1017 ions cm-2 at energy of 100 keV. The dose of 2.0x1017 ions cm-2 and energy of 100 were the best implantation parameter in this study.

STUDY OF THE MICROSTRUCTURE OF MARTENSITE-BAINITE STEELS AND NICKEL ALLOYS WHEN MODELING HEAT TREATMENT MODES USING A DILATOMETRIC METHOD

2019 ◽  
Vol 85 (6) ◽  
pp. 30-36
Author(s):  
N. V. Lebedeva ◽  
Yu. M. Markova ◽  
A. I. Ziza ◽  
D. M. Anisimov
Keyword(s):  
Heat Treatment ◽  
Thermomechanical Processing ◽  
Production Costs ◽  
Grain Structure ◽  
Helium Atmosphere ◽  
Fine Grained ◽  
Dilatometric Method ◽  
Combined Application ◽  
Fine Grained Structure

We present the results obtained using the equipment available at the Center for collective use “Composition, structure, properties of structural and functional alloys” NRC “Kurchatov Institute” — CRISM “Prometey”: DIL 805A/D (TA Instruments) and DIL 402C (Netzsch) dilatometers. Dilatometric analysis which provides determination of the temperature coefficient of linear expansion and the temperature of phase transitions, as well as evaluation of the transformation kinetics, can also allow simulation of heat treatment modes to identify the size of the former austenitic grain using vacuum etching and conduct the research aimed at improving the technology of thermal and thermomechanical processing (TMO) of steels and alloys. The experiments were carried out both in vacuum and in dynamic helium atmosphere. The main methodological difficulties that we have faced with are described. For steels of martensite and martensite-bainite class (38KhMA, 38KhN3MFA, 20Kh3NMFA) conditions of vacuum etching in the chamber of the dilatometer are specified. The efficiency of the method for martensite-bainite steels in determination of the grain size compared to traditional methods of etching is deminstrated. The effect of thermodeformation parameters on the size of austenitic grain is estimated. When modeling the heat treatment modes by the dilatometric method, the microstructure of KhN55MVTs nickel alloy was also analyzed. Changes in the size and morphology of the grain structure at different stages of heat treatment are revealed. The obtained results were used to adjust the current modes of heat treatment and obtain a uniform fine-grained structure. The combined application of dilatometric and metallographic analyzes after vacuum etching of the material decreases the production costs attributed to obtaining the desired microstructure upon thermal and thermomechanical processing of the products and blanks.

THERMAL OXIDATION OF Ti6Al4V ALLOY WITH ENHANCED WEAR AND CORROSION RESISTANCE FOR OIL AND GAS APPLICATION: EFFECT OF TEMPERATURE

2015 ◽  
Vol 22 (03) ◽  
pp. 1550033 ◽  
Author(s):  
NAIMING LIN ◽  
PENG ZHOU ◽  
YATING WANG ◽  
JIAOJUAN ZOU ◽  
YONG MA ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Corrosion Resistance ◽  
Thermal Oxidation ◽  
Oil And Gas ◽  
Surface Hardness ◽  
Effect Of Temperature ◽  
Wear And Corrosion ◽  
Different Temperatures ◽  
Superior Corrosion Resistance ◽  
Wear And Corrosion Resistance

Thermal oxidation (TO) treatments were performed at 873 K, 898 K, 923 K, 948 K, 973 K, 998 K and 1023 K for 10 h in air to improve the wear and corrosion resistance of Ti 6 Al 4 V alloy. The effect of TO temperature on microstructural characterizations and surface properties of the obtained TO layers were investigated. The results showed that TO layers with various thickness values were formed on Ti 6 Al 4 V alloy under different temperatures. The thickness of the TO layers increased with the increasing of TO temperature. TO layer that was obtained at 973 K suggested the highest surface hardness and the best wear resistance. TO layer that was realized at 948 K exhibited superior corrosion resistance to other TO layers. TO treatment could be considered as an effective method for preventing wear and corrosion of Ti 6 Al 4 V alloy.

Corrosion Resistance of TiN Coating on 304 Steel

2011 ◽  
Vol 121-126 ◽  
pp. 3779-3783
Author(s):  
Shiuh Chuan Her ◽  
Cheng Lin Wu
Keyword(s):  
Corrosion Resistance ◽  
Magnetron Sputtering ◽  
Substrate Temperature ◽  
Steel Substrate ◽  
High Surface ◽  
Surface Hardness ◽  
Deposition Parameters ◽  
Wear And Corrosion ◽  
Tin Thin Films ◽  
Wear And Corrosion Resistance

Titanium Nitride (TiN) coatings with high surface hardness, good wear and corrosion resistance, low friction coefficient have been widely used in many applications such as a hard coating of cutting tool, a diffusion barrier layer. In this work, TiN thin films were deposited by D.C. magnetron sputtering process on SUS 304 steel substrate. Magnetron sputtering provides a wide variation of the deposition parameters which affect the morphology of the films and, consequently, their properties. The effects of substrate temperature on the microstructure and corrosion resistance of TiN films were studied in details using atomic force microscopy and potentiostat test. Considerable improvements in the surface roughness and corrosion resistance were observed when the substrate temperature was increased from C to C.

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