scholarly journals Microstructural Features and Surface Hardening of Ultrafine-Grained Ti-6Al-4V Alloy through Plasma Electrolytic Polishing and Nitrogen Ion Implantation

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 696
Author(s):  
Marina K. Smyslova ◽  
Roman R. Valiev ◽  
Anatoliy M. Smyslov ◽  
Iuliia M. Modina ◽  
Vil D. Sitdikov ◽  
...  
Keyword(s):  
Surface Layer ◽  
Ion Implantation ◽  
Surface Hardening ◽  
High Energy ◽  
Coarse Grained ◽  
Α Phase ◽  
Electrolytic Polishing ◽  
Ultrafine Grained ◽  
Phase Size ◽  
Plasma Electrolytic

This work studies a near-surface layer microstructure in Ti-6Al-4V alloy samples subjected to plasma electrolytic polishing (PEP) and subsequent high-energy ion implantation with nitrogen (II). Samples with a conventional coarse-grained (CG) structure with an average α-phase size of 8 μm and an ultrafine-grained (UFG) structure (α-phase size up to 0.35 μm) produced by equal channel angular pressing were used in the studies. Features of phase composition and substructure in the thin surface layers are shown after sequential processing by PEP and II of both substrates with CG and UFG structures. Irrespective of a substrate structure, the so-called “long-range effect” was observed, which manifested itself in enhanced microhardness to a depth of surface layer up to 40 μm, exceeding the penetration distance of an implanted ion he. The effect of a UFG structure on depth and degree of surface hardening after PEP and ion-implantation is discussed.

Ultrafine-grained microstructure in a Cu–Zn alloy produced by electropulsing treatment

2003 ◽  
Vol 18 (8) ◽  
pp. 1991-1997 ◽  
Author(s):  
Yizhou Zhou ◽  
Wei Zhang ◽  
Baoquan Wang ◽  
Jingdong Guo
Keyword(s):  
High Current Density ◽  
Coarse Grained ◽  
Heating And Cooling ◽  
Β Phase ◽  
Α Phase ◽  
Ultrafine Grained ◽  
Solid State Phase Transformation ◽  
Two Phases ◽  
Electropulsing Treatment ◽  
Zn Alloy

High-current-density electropulsing was applied to a coarse-grained Cu–Zn alloy with two phases of α-phase and β′-phase. It was found that with an electropulsing treatment, ultrafine-grained (UFG) microstructure could be formed in the α-phase, but could not be formed in the β-phase. The results indicated that the formation of UFG microstructure was dependent on solid-state phase transformation. The main reason for the formation of UFG microstructure by electropulsing treatment resulted from the effect of a decrease in thermodynamic barrier and enhancement of nucleation rate in a current-carrying system, but not from the high heating and cooling rate during electropulsing treatment. The bulk UFG samples prepared by electropulsing treatment were free of porosity and contamination and had no large microstrain. It was reasonable to anticipate that a new method might be developed to produce ideal bulk UFG samples directly from the conventional coarse-grained materials by application of electropulsing.

scholarly journals Phase Transformations upon Ageing in Ti15Mo Alloy Subjected to Two Different Deformation Methods

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1230
Author(s):  
Kristína Bartha ◽  
Josef Stráský ◽  
Anna Veverková ◽  
Jozef Veselý ◽  
Jakub Čížek ◽  
...  
Keyword(s):  
High Pressure Torsion ◽  
Positron Annihilation Spectroscopy ◽  
Lattice Defects ◽  
Coarse Grained ◽  
Two Phase ◽  
Rotary Swaging ◽  
Α Phase ◽  
Ultrafine Grained ◽  
Isothermal Ageing ◽  
Α Particles

Ti15Mo alloy was subjected to two techniques of intensive plastic deformation, namely high pressure torsion and rotary swaging at room temperature. The imposed strain resulted in the formation of an ultrafine-grained structure in both deformed conditions. Detailed inspection of the microstructure revealed the presence of grains with a size of around 100 nm in both conditions. The microstructure after rotary swaging also contained elongated grains with a length up to 1 µm. Isothermal ageing at 400 °C and 500 °C up to 16 h was applied to both conditions to investigate the kinetics of precipitation of the α phase and the recovery of lattice defects. Positron annihilation spectroscopy indicated that the recovery of lattice defects in the β matrix had already occurred at 400 °C and, in terms of positron trapping, was partly compensated by the precipitation of incoherent α particles. At 500 °C the recovery was fully offset by the formation of incoherent α/β interfaces. Contrary to common coarse-grained material, in which the α phase precipitates in the form of lamellae, precipitation of small and equiaxed α particles occurred in the deformed condition. A refined two-phase equiaxed microstructure with α particles and β grain sizes below 1 μm is achievable by simple rotary swaging followed by ageing.

High Energy Surface Implantation by Ion Nitrogen of Ultra- Fine Grained Ti-6Al-4V Alloy for Engineering Application

2021 ◽  
Vol 1016 ◽  
pp. 1305-1311
Author(s):  
Irina Semenova ◽  
Marina Smyslova ◽  
Konstantin Selivanov ◽  
Vil Sitdikov ◽  
Roman Valiev
Keyword(s):  
Ion Implantation ◽  
Engineering Application ◽  
High Energy ◽  
X Ray Diffraction ◽  
Scratch Testing ◽  
Fine Grained ◽  
Angular Pressing ◽  
Low Temperature Annealing ◽  
Ultrafine Grained ◽  
Number Of Cycles

This paper aims to study the peculiarities of a modified layer in the surface of ultrafine-grained (UFG) Ti-6Al-4V alloy after high energy ion nitrogen implantation. The UFG structure in the alloy was produced by equal channel angular pressing. X-ray diffraction analysis and scratch-testing were applied for the investigation. The influence of low-temperature annealing (400°C during 1 hour) on the substructure parameters and phase composition of the surface layer depending on a number of cycles of ion implantation with annealing was shown in the research. The effect of the UFG structure on mechanisms and strengthening degree of the surface after ion implantation is discussed.

scholarly journals Formation of Silicon Carbide in the Surface Layer of Metals by Dual High Energy Ion Implantation

1999 ◽  
Vol 40 (5) ◽  
pp. 428-430 ◽  
Author(s):  
Syouhei Taniguchi ◽  
Akiharu Kitahara ◽  
Shuichi Wakayama
Keyword(s):  
Silicon Carbide ◽  
Surface Layer ◽  
Ion Implantation ◽  
High Energy

Long Period Gratings in Multimode Fiber Fabricated with High-Energy Ion Implantation

2003 ◽  
Vol 22 (4) ◽  
pp. 225-237
Author(s):  
K. J. GRANT ◽  
ROBERTS A. ◽  
D. N. JAMIESON ◽  
B. ROUT ◽  
C. CHER
Keyword(s):  
Ion Implantation ◽  
High Energy ◽  
Multimode Fiber ◽  
Long Period ◽  
Long Period Gratings

Utilisation of High-Energy Heat Sources in Magnesium Alloy Surface Layer Treatment

2013 ◽  
Vol 58 (2) ◽  
pp. 619-624 ◽  
Author(s):  
M. Szafarska ◽  
J. Iwaszko ◽  
K. Kudła ◽  
I. Łegowik
Keyword(s):  
Surface Layer ◽  
Magnesium Alloy ◽  
Physicochemical Properties ◽  
Treatment Effectiveness ◽  
High Energy ◽  
Alloy Surface ◽  
Heat Sources ◽  
X Ray ◽  
Additional Equipment ◽  
Alloy Surface Layer

The main aim of the study was the evaluation of magnesium alloy surface treatment effectiveness using high-energy heat sources, i.e. a Yb-YAG Disk Laser and the GTAW method. The AZ91 and AM60 commercial magnesium alloys were subject to surface layer modification. Because of the physicochemical properties of the materials studied in case of the GTAW method, it was necessary to provide the welding stand with additional equipment. A novel two-torch set with torches operating in tandem was developed within the experiment. The effectiveness of specimen remelting using a laser and the GTAW method was verified based on macro- and microscopic examinations as well as in X-ray phase analysis and hardness measurements. In addition, the remelting parameters were optimised. The proposed treatment methodology enabled the achieving of the intended result and effective modification of a magnesium alloy surface layer.

Theoretical justifi cation for use of combined methods for hardening of surfaces of machine parts in order to control their fretting resistance

2020 ◽  
pp. 339-342
Author(s):  
V.F. Bez’yazychny ◽  
M.V. Timofeev ◽  
R.V. Lyubimov ◽  
E.V. Kiselev
Keyword(s):  
Surface Layer ◽  
Fatigue Limit ◽  
Surface Hardening ◽  
Theoretical Justification ◽  
Hardening Process ◽  
Subsequent Application ◽  
Machine Parts ◽  
Combined Methods

The theoretical justification for the hardening process of the surface layer of machine parts for combined methods of surface hardening with subsequent application of strengthening coatings, as well as reducing or increasing the fatigue limit due to the fretting process is presented.

Use of ultrasonic surface hardening in modifi cation of surface layer

2020 ◽  
pp. 200-204
Author(s):  
Yu.S. Semenova ◽  
A.G. Samul’ ◽  
S.V. Mazhuga
Keyword(s):  
Surface Layer ◽  
Chemical Treatment ◽  
Surface Hardening ◽  
Manufacturing Cost ◽  
Ultrasonic Vibrations ◽  
Surface Microrelief ◽  
Scientific Schools ◽  
Structure Changes ◽  
Wide Range ◽  
Finishing Machining

Overview of the research results got by various scientific schools in the field of application of ultrasonic surface hardening is provided. Wide range of opportunities of ultrasonic surface hardening is shown for the application in the preliminary machining of surfaces before thermal and chemical treatment, coating, and also as finishing machining. The effect of the energy of ultrasonic vibrations on structure changes in the material of the surface layer and on surface microrelief on parts performance is considered. The prospects of using of the ultrasonic surface hardening method in combination with other methods of the material modification are presented. In addition the possibilities of reducing the manufacturing cost of product by introducing ultrasonic surface hardening into the technological process are shown.

Melt Modification and Microstructure Homogeneity of Solidified TiC-TiB2 Composites Prepared by Combustion Synthesis in Ultrahigh Gravity Field

2013 ◽  
Vol 833 ◽  
pp. 125-129
Author(s):  
Hao Zhang ◽  
Zhong Min Zhao ◽  
Long Zhang ◽  
Shuan Jie Wang
Keyword(s):  
Gravity Field ◽  
Combustion Synthesis ◽  
Stokes Flow ◽  
High Energy ◽  
Adiabatic Temperature ◽  
Full Density ◽  
Reactive System ◽  
Refined Microstructure ◽  
Ultrafine Grained ◽  
Ultrafine Grained Microstructure

By introducing (CrO3+Al) high-energy thermit into (Ti+B4C) system and designing adiabatic temperature of reactive system as 3000°C,3200°C, 3400°C, 3600°C and 3800°C respectively, a series of solidified TiC-TiB2were prepared by combustion synthesis in ultrahigh gravity field with the acceleration 2000 g. XRD, FESEM and EDS results showed that the solidified TiCTiB2were composed of a number of TiB2primary platelets, irregular TiC secondary grains, and a few of isolated Al2O3inclusions and Cr-based alloy. Because of the enhanced Stokes flow in mixed melt with the increased adiabatic temperature, Al2O3droplets were promoted to float up and separate from TiC-TiB2-Me liquid while constitutional distribution became more and more uniform in TiC-TiB2-Me liquid, resulting in not only the sharply-reduced Al2O3inclusions in the solidified ceramic but also the refined microstructure and the improved homogeneity in the ceramic, and ultrafine-grained microstructure with a average thickness of TiB2platelets smaller than 1μm began to appear in near-full-density ceramic as the adiabatic temperature exceeded 3600°C, so the densification, fracture toughness and flexural strength of the ceramic were enhanced with the increased adiabatic temperature of the reactive system.

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