Effects of the Laser Power on the Microstructure and Microhardness of the Carbonitrided 45 Steel

2013 ◽  
Vol 291-294 ◽  
pp. 2613-2616
Author(s):  
Hong Mei Zhu ◽  
Ru Shu Peng ◽  
Chao Hui Weng
Keyword(s):  
Heat Treatment ◽  
Electron Microscope ◽  
Laser Power ◽  
Homogeneous Element ◽  
Element Distribution ◽  
Laser Remelting ◽  
Microstructure Morphology ◽  
The Given ◽  
Scanning Electron ◽  
Microhardness Tester

The 45 steel was processed by laser remelting after the carbonitriding heat treatment in this study. The microstructure morphology and microhardness of the laser-remelting layer at different laser powers were investigated by scanning electron microscope (SEM) and microhardness tester, respectively. The results show that a compact microstructure and a homogeneous element distribution can be achieved at the laser power of 1.2 kW under the given other laser parameters, and the microhardness was enhanced greatly.

EFFECT OF HEAT TREATMENT ON MICROSTRUCTURE CHARACTERISTICS OF LASER COMPOSITES

2014 ◽  
Vol 21 (01) ◽  
pp. 1450014
Author(s):  
PENG LIU ◽  
YUANBIN ZHANG ◽  
YAJIANG LI ◽  
QINGQING YANG ◽  
YAN LIU ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Electron Microscope ◽  
Theoretical Basis ◽  
Laser Alloying ◽  
Wear Properties ◽  
Microstructure Characteristics ◽  
Transmission Electron ◽  
Treatment Technologies ◽  
Intensity Transfer ◽  
Scanning Electron

In this paper, effect of heat treatment on the microstructures and wear properties of laser alloying (LA) composites is investigated. LA of the T - Co 50/ FeSi / TiC / TiN / CeO 2 mixed powders on substrate of 45 steel can form the hard composites, which increased the wear resistance of substrate greatly. Such LA composites were investigated by means of a scanning electron microscope (SEM) and a transmission electron microscope (TEM). The tempering promoted the growth of the block-shape hard phases, favoring an enhancement of the integrity of block-shape hard phases; and tempering also improved greatly the formation mechanism, guarantying the composites to have enough ability of intensity transfer. This research provided essential experiment and theoretical basis to promote the application of the laser and heat treatment technologies in the field of surface modification.

Effect of Double-Step Solution Treatment on Rejuvenation Heat Treated Microstructure of IN-738 Superalloy

2020 ◽  
Vol 856 ◽  
pp. 36-42
Author(s):  
Chuleeporn Paa-Rai
Keyword(s):  
Heat Treatment ◽  
Image Analysis ◽  
Electron Microscope ◽  
Solution Treatment ◽  
Single Step ◽  
Double Step ◽  
Heat Treated ◽  
Cast Superalloy ◽  
Scanning Electron

This work investigates the effect of rejuvenation heat treatment, with double-step solution treatment at the temperature from 1150 °C to 1200 °C, on the recovered microstructure of IN-738 cast superalloy. The superalloy has been long-term exposed as a turbine blade in a gas turbine prior to this study. After double solution treatment and aging at 845 °C for 12 h and 24 h, the recovered microstructures were examined by using a scanning electron microscope. Coarse γ΄ particles, that have presented in damaged microstructures, could not be observed in the samples after the rejuvenation heat treatment. In addition, the image analysis illustrates that the reprecipitated γ΄ particles in the samples with double-step solution treatments increase significantly in sizes during aging than that in the samples with the single-step solution treatment. Furthermore, the measurement of the samples hardness presents that the as-receive sample hardness is improved after rejuvenation heat treatment studied in this work.

Effect of VC and C Addition on Mechanical Properties and Microstructures of WC-Co Hardmetals Processed in Nitrogen-Based Atmosphere

2012 ◽  
Vol 59 (2) ◽  
Author(s):  
R. J. Talib ◽  
A. A. Mahaidin ◽  
S. A. Manaf ◽  
M. A. Selamat
Keyword(s):  
Mechanical Properties ◽  
Electron Microscope ◽  
Powder Metallurgy ◽  
Test Results ◽  
Powder Metallurgy Technique ◽  
Dense Structure ◽  
Mixed Powder ◽  
Vicker’S Microhardness ◽  
Scanning Electron ◽  
Microhardness Tester

The WC-Co, WC-Co-VC and WC-Co-C samples are fabricated using powder metallurgy technique. The mixed powder is compacted under the pressure of 625 MPa, cold-isostatic pressed at 200 MPa and sintered at temperature in the range of 1350 – 1450°C nitrogen-based atmosphere. The mechanical properties of the samples are analyzed using Vicker’s microhardness tester, universal tensile machine and scanning electron microscope. Test results reveal that WC-Co-C sample has better mechanical properties as compared to WC-Co and WC-Co-VC due to the formation of homogeneous and dense structure.

Laser power and scanning speed influence on the microstructure, hardness, and slurry erosion performance of Colmonoy-5 claddings

2020 ◽  
Vol 234 (7) ◽  
pp. 947-961
Author(s):  
T Savanth ◽  
Jastej Singh ◽  
JS Gill
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Laser Processing ◽  
Laser Power ◽  
Erosive Wear ◽  
Scanning Speed ◽  
Processing Parameters ◽  
X Ray ◽  
High Scanning Speed ◽  
Scanning Electron

A 4kW Yb: YAG solid-state disc laser, with a four-way co-axial cladding head with powder feeding technique was employed to fabricate single-layer clads of Ni-based hardfacing alloy (Colmonoy-5) on medium carbon steel (ASME SA105) substrate by varying the laser processing parameters namely, beam power level (designated as low: 1200 W, medium: 1400 W, and high: 1600 W) and scanning speed (designated as low: 300 mm/min, medium: 400 mm/min, and high: 500mm/min). The laser clads were evaluated for their microstructural characteristics, microhardness, and slurry erosive wear performance with an aim to understand the effect of process parametric variations on their properties. Microstructural analyses of the clads were carried out using an optical microscope and a field-emission scanning electron microscope with attached energy-dispersive X-ray spectrometer supplemented by their Vickers microhardness testing and X-ray diffraction examination. The variation in laser processing parameters exerted a strong influence on the microstructural features of the clads in terms of γ-Ni dendrite size as well as morphology and distribution of various complex precipitates such as Cr-carbides and borides with relatively uniform distribution observed for the clads corresponding to low laser power and high scanning speed. The variation in laser power had relatively a greater influence on microhardness than the scanning speed variation. Micro-cutting, plastic deformation, crater formation besides ploughing away of the softer matrix were the typical fracture features associated with slurry eroded clads when examined under field-emission scanning electron microscope. Results of the slurry erosive wear tests showed that the clads pertaining to low laser power and high scanning speed exhibited superior wear resistance as compared to their counterparts.

"In Situ-Tracking” Evaluation for Corrosion Progress at Fusion Boundary of Dissimilar Steel Welded Joints in H2S Containing Solution

2007 ◽  
Vol 561-565 ◽  
pp. 2245-2248
Author(s):  
Chun Xu Pan ◽  
Qiang Fu
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Electron Microscope ◽  
Welded Joint ◽  
Corrosion Property ◽  
Post Weld Heat Treatment ◽  
Fusion Boundary ◽  
Dissimilar Steel ◽  
Scanning Electron

The present work studied the corrosion property around the fusion boundaries of a dissimilar steel welded joint in as-welded condition and after post-weld heat treatment (PWHT) in H2S containing solution with different times. An “in-situ-tracking” observation was proceeded for evaluating corrosive progress at the fusion boundary by using a scanning electron microscope (SEM). The results revealed that the fusion boundary was the worst region for corrosion resistance when comparing with other zones, and a broad boundary had a stronger resistance for “hydrogen induced disbonding” than a narrow one.

scholarly journals Effects of heat treatment and strain rate on the microstructure and mechanical properties of 6061 Al alloy

2015 ◽  
Vol 25 (1) ◽  
pp. 26-41 ◽  
Author(s):  
Ling Li ◽  
EA Flores-Johnson ◽  
Luming Shen ◽  
Gwénaëlle Proust
Keyword(s):  
Heat Treatment ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Electron Back Scatter Diffraction ◽  
Micro Cracks ◽  
Strain Rate Compression ◽  
Scanning Electron

In the present work, the effects of heat treatment and strain rate on mechanical behaviour and microstructure evolution of aluminium alloy 6061 have been investigated. The micro-crack initiation and crystallographic texture evolution are obtained from scanning electron microscope and electron back-scatter diffraction experiments. Quasi-static and high strain rate compression tests are conducted on AA6061 specimens that underwent two different heat treatments: the as-received material with the original T6 heat treatment and the heat treated and artificially aged specimens. For the high strain rate compression (∼2000 and ∼4000 s−1) tests, the split Hopkinson pressure bar apparatus is used. It is observed that the additional heat treatment has significantly reduced the yield strength of the material. Furthermore, electron back-scatter diffraction results show that the higher the applied strain rate is, the less significant change will happen to the texture. Scanning electron microscope images show that, for both T6 and HT specimens, the number and size of micro-cracks in the dynamic compressed specimens are smaller than in the quasi-static deformed specimen. Therefore, the strain rate is considered to be the dominant factor in forming micro-cracks.

Microstructural Rejuvenation Through Non-conventional Heat Treatments of an Inconel 939 Superalloy

2012 ◽  
Vol 1372 ◽  
Author(s):  
M. A. González ◽  
D. I. Martínez ◽  
A. Pérez ◽  
H. Guajardo
Keyword(s):  
Heat Treatment ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Heat Treatments ◽  
Homogeneous Microstructure ◽  
Conventional Microscopy ◽  
Cast Superalloy ◽  
Scanning Electron

ABSTRACTThe microstructural rejuvenation through non-conventional heat treatments (NCHT) of a conventional cast superalloy Inconel 939 was investigated. The primary and secondary main constituents of the NCHT microstructures were characterized through its morphology and composition applying conventional microscopy and analytical scanning electron microscope (SEM). The results showed a complete rejuvenation of the overage microstructure (disordered coarse cuboids of 1.2μm from γ´, continuous films of M23C6 carbides and coarse MC carbides as well as γ-γ´eutectics) into a more homogeneous microstructure; spherical ordered primary γ´ and secondary γ´ precipitates ranging between 357 to 442 nm and 30 to50 nm respectively and depending on the applied heat treatment. Also blocky type MC and discreet M23C6 carbides dispersed within the dendrite and in the interdendritic regions were observed. There was no evidence of the formation of detrimental phases with the NCHT, which can affect the long-term properties of the alloy during service.

Cavitation Wearing of the SUPERSTON Alloy after Laser Treatment at Cryogenic Conditions

2010 ◽  
Vol 165 ◽  
pp. 306-309 ◽  
Author(s):  
Beata Majkowska ◽  
Waldemar Serbiński
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Laser Treatment ◽  
Cross Section ◽  
Base Material ◽  
Cavitation Resistance ◽  
Laser Remelting ◽  
Rotating Disc ◽  
Cryogenic Conditions ◽  
Scanning Electron

The purpose of this paper is to demonstrate the method of laser remelting at cryogenic conditions of the SUPERSTON alloy and its influence on microstructure and cavitation wearing. The cavitation test was performed using the rotating disc facility in IPM PAN Gdansk. During the cavitation test, the mass loss of the material with different parameters of laser remelting was determined. Surface and cross-section microstructure of the SUPERSTON alloy after laser treatment and cavitation test were observed by scanning electron microscope. The cavitation resistance of the remelted SUPERSTON alloy was approximately 40% higher in comparison to the base material.

scholarly journals PENGAMATAN STRUKTUR MIKRO PADA KOROSI ANTAR BUTIR DARI MATERIAL BAJA TAHAN KARAT AUSTENITIK SETELAH MENGALAMI PROSES PEMANASAN

2009 ◽  
Vol 3 (2) ◽  
pp. 107
Author(s):  
Anwar Budianto ◽  
Kristina Purwantini ◽  
BA Tjipto Sujitno
Keyword(s):  
Heat Treatment ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Holding Time ◽  
Energy Dispersive ◽  
X Ray ◽  
Ss 304 ◽  
Scanning Electron

PENGAMATAN STRUKTUR MIKRO PADA KOROSI ANTAR BUTIR DARI MATERIAL               BAJA      TAHAN KARAT                             AUSTENITIK             SETELAH MENGALAMI PROSES HEAT PEMANASAN. Telah dilakukan pengamatan korosi  antar  butir pada  material  baja tahan karat  austenitik  jenis  SS 304 setelah mengalami proses perlakuan panas (heat treatment) pada selang suhu (400-950) oC dengan variasi waktu pemanasan (holding time) yaitu 1 jam, 3 jam, 3,5 jam, dan  4 jam.  Sebelum dan sesudah proses perlakuan panas, struktur mikro sampel dianalisis menggunakan   mikroskop   optik   dan   SEM   (Scanning   Electron   Microscope). Komposisi kimia pada daerah di sekitar batas butir diamati menggunakan SEM-EDS (Energy  Dispersive  X-ray  Spectrometer).  Hasil  pengamatan  menunjukkan  bahwasampel yang mengalami perlakuan panas di bawah suhu sensitisasi yakni pada suhu400 oC, ternyata korosi antar butir tidak teramati. Untuk sampel yang mengalami perlakuan panas pada suhu sensitisasi yakni pada selang suhu (500-900) oC, ternyata korosi antar butir dapat teramati dengan jelas. Sedangkan untuk sampel yang mengalami perlakuan panas di atas suhu sensitisasi yaitu pada suhu 950 oC, ternyata korosi antar butir masih dapat teramati tetapi tidak sejelas sampel yang mengalami perlakuan panas pada suhu sensitisasi. Dari analisis komposisi kimia di sekitar batas butir ditemukan adanya penurunan kandungan karbon (C) yaitu dari 0,61 % massamenjadi 0,47 %massa, dan untuk khrom (Cr) dari 18,37 % massa menjadi 17,76 %massa. 

scholarly journals 1D NiO-SnO2 Heterojunction Nanofibers as Acetone Sensor

2016 ◽  
Vol 1 (1) ◽  
pp. 172 ◽  
Author(s):  
W. Tang ◽  
J. Wang
Keyword(s):  
Heat Treatment ◽  
Electron Microscope ◽  
Energy Level ◽  
Gas Sensors ◽  
X Ray Diffraction ◽  
X Ray ◽  
P Type ◽  
Type Response ◽  
Acetone Sensor ◽  
Scanning Electron

<p>1D NiO-SnO<sub>2</sub> nanofibers with p-n heterostructure were synthesized by electrospinning with post-synthetic heat treatment. The morphology and composition were characterized by scanning electron microscope, X-ray diffraction, and energy dispersive X-ray spectrometry. A possible growth model was proposed to describe the formation of hierarchical NiO-SnO<sub>2</sub>. The gas sensors based on NiO-SnO<sub>2</sub> exhibited p-type response to acetone. The excellent acetone sensing properties may be attributed to numerous p-n junctions between NiO and SnO<sub>2</sub> nanograins as well as the unique architecture. The changes of energy level and space charge layer of NiO-SnO<sub>2</sub> heterojunction nanofibers when exposed to acetone are described in detail.</p>

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