The dependency of the microhardnes on microstructure and solidification parameters of directionally solidified Al–4.5wt.%Cu in clay mold

2020 ◽  
Vol 14 (3) ◽  
pp. 7125-7131
Author(s):  
Dedy Masnur ◽  
Viktor Malau ◽  
Suyitno Suyitno
Keyword(s):  
Solidification Process ◽  
Optical Microscope ◽  
Cooling Curve ◽  
Mold Material ◽  
Micro Hardness ◽  
Directionally Solidified ◽  
Steel Mold ◽  
Hardness Tester ◽  
Microstructure Parameters ◽  
Solidification Parameters

Improvement of material properties is achieved by controlling parameters involved in the solidification process; therefore, understanding them and their implication are essential. This work investigated the dependency of solidification parameters (cooling rate (TR), growth rate (VL), local solidification time (tSL), temperature gradient (G)), microstructure parameters (primary (λ1) and secondary (λ2) dendrite arm spacing), and micro-hardness values (HV) of Al-4.5wt.%Cu in the clay mold. The samples were directionally solidified in Bridgman vertical apparatus and the temperature is recorded during the cooling. The solidification parameters were obtained from the cooling curve. The microstructures and micro-hardness were characterized using an optical microscope and micro-hardness tester. The microstructure parameters were measured and plotted as functions of solidification parameters using linear regression. The relation between HV and microstructure parameters are analyzed. The results show the λ1 and λ2 change inversely with solidification parameters except for tSL. Comparison to other works shows the exponent values of solidification parameters of the clay mold are lower than that of the carbon and stainless-steel mold. The exponent value of λ2 in the clay mold is -0.183, close to the value in the graphite mold. The clay has the potential as mold material since it characteristic close to the graphite.

Evolutions of Microstructure for Multilayered Al-Mg Alloy Composites by Accumulation Roll Bonding (ARB) Process

2011 ◽  
Vol 411 ◽  
pp. 527-531
Author(s):  
Bing Zhang ◽  
Zhong Wei Chen ◽  
Shou Qian Yuan ◽  
Tian Li Zhao
Keyword(s):  
Multilayer Structure ◽  
Optical Microscope ◽  
Alloy Layer ◽  
Mg Alloy ◽  
Micro Hardness ◽  
Roll Bonding ◽  
Fine Grained ◽  
Hardness Tester ◽  
Average Grain Size ◽  
Evolution Of Microstructure

In this paper, accumulative roll bonding (ARB) has been used to prepare the Al/Mg alloy multilayer structure composite materials with 1060Al sheet and MB2 sheet. The evolution of microstructure of the cladding materials during ARB processes was observed by optical microscope, scanning electron microscopy, and micro-hardness was measured by micro-hardness tester. The results show that a multilayer structure material of Al/Mg alloy with excellent bonding characteristics and fine grained microstructure was prepared by ARB processes. With the ARB cycles increasing, Mg alloy layer in multilayer composite material was necked and fractured, and the hardness of the Al and Mg alloy was increased. Average grain size was less than 1μm after ARB4 cycles.

scholarly journals Influence of the resistive-pulse welding parameters of nickel super-alloys on selected properties of the connection

Mechanik ◽  
2017 ◽  
Vol 90 (11) ◽  
pp. 1060-1062
Author(s):  
Sławomir Spadło ◽  
Wojciech Depczyński ◽  
Piotr Młynarczyk ◽  
Tadeusz Gajewski ◽  
Jarosław Dąbrowa
Keyword(s):  
Optical Microscope ◽  
Mechanical Tests ◽  
Welding Parameters ◽  
Thin Sheets ◽  
Micro Hardness ◽  
Hastelloy X ◽  
Haynes 230 ◽  
Hardness Tester ◽  
Resistive Pulse ◽  
Pulse Welding

Microstructure and mechanical tests of welds of thin sheets made from nickel-based super-alloys (Haynes 230 and Hastelloy X) were presented. The welds were made using the resistive-pulse micro-welding method using the WS 7000S device. The micro-hardness of the joints was measured with a Matsuzawa Vickers MX 100 hardness tester at 100 G (0.98 N). Metallographic observations of the prepared micro-sections were performed using the Nikon Eclipse MA200 optical microscope at various magnifications. The metallographic microstructure studies were supplemented by linear analysis of the chemical composition, for which the OXFORD X-MAX electron microscope was applied.

Investigation on Recovery and Recrystallization of Al-Si-Al2O3 Composites

2013 ◽  
Vol 813 ◽  
pp. 345-350
Author(s):  
Xiong Wei Wang ◽  
Xiao Song Jiang ◽  
De Gui Zhu ◽  
Luo Zhang
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Optical Microscope ◽  
In Situ Synthesis ◽  
Recrystallization Temperature ◽  
Recrystallization Behavior ◽  
Micro Hardness ◽  
Hardness Tester ◽  
Scanning Electron

Al-Si-Al2O3 composites were prepared by powder metallurgy with in-situ synthesis technology. The recovery and recrystallization behavior of Al-Si-Al2O3 composites which underwent compression and then heat-treatment under different temperature were studied using micro-hardness tester, optical microscope (OM) and scanning electron microscopy (SEM) . The results showed that the hardness of composites increased dramatically after compression, and the sample containing 5wt% Si was increasing more evidently than the sample including 10wt%Si. Heat treatment gradually eliminated work hardening; meanwhile the fact that the hardness of composites trended to decline greatly when subjected to annealing suggested occurrence of recovery and recrystallization inside the composites. Recrystallization nucleation preferentially took place in the region near the particle, while the growth of recrystallized grains can also be hindered owning to the pining effect of particles. Depending on the analysis of microstructure and microhardness, it can be concluded that the recrystallization temperature of Al-wt.5%Si-Al2O3 composites was 500°C and the Al-wt.10%Si-Al2O3 composites was 525°C.

Characterisation of WC-17Co and WC-9Ni HVOF Sprayed Cermet Coatings

2016 ◽  
Vol 840 ◽  
pp. 331-335
Author(s):  
Nur Amira Mohd Rabani ◽  
Zakiah Kamdi
Keyword(s):  
Steel Substrate ◽  
Optical Microscope ◽  
Binder Phase ◽  
High Porosity ◽  
Tungsten Carbides ◽  
Micro Hardness ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hardness Tester ◽  
Vickers Micro Hardness

Cemented tungsten carbides have been paid much attention due its better mechanical properties with excellent combination of hardness and toughness characteristics. The hard WC particles in the coating provide hardness and wear resistance, while the ductile binder such as Co and Ni contribute to toughness and strength. WC-17wt.% Co and WC-9wt.% Ni powders have been sprayed by the HVOF method to form coatings approximately 300μm and 150μm thick onto AISI 1018 steel substrate. Both coatings have been prepared and supplied by an external vendor. The coatings were examined using optical microscope (OM), scanning electron microscope (SEM), and X-Ray diffraction (XRD). The hardness of both coatings were also measured using Vickers micro-hardness tester. The microstructure of the coatings has been analyzed and found to consist of WC, brittle W2C phase, metallic W phase, and amorphous binder phase of Co and Ni. It is found that WC-Ni has a higher hardness value compared to WC-Co due to high porosity distribution.

The Effects on Microstructure and Hardness of 0.28% Vanadium and 0.87% Nickel Alloyed Ductile Iron after Boronizing Process

2017 ◽  
Vol 740 ◽  
pp. 65-69 ◽  
Author(s):  
Khalissah Muhammad Yusof ◽  
Bulan Abdullah ◽  
Mohd Faizul Idham ◽  
Nor Hayati Saad
Keyword(s):  
Ductile Iron ◽  
Optical Microscope ◽  
Boride Layer ◽  
Holding Time ◽  
Material Surface ◽  
Micro Hardness ◽  
Surface Layers ◽  
Hardness Tester ◽  
Double Phase ◽  
Wear And Corrosion

Boronizing/boriding is a thermo mechanical process which produced protective surface layers to enhance the performance of engineering components utilized in mechanical, wear and corrosion. The present study investigate the microstructure and the hardness of boride layers formed on 0.28% Vanadium and 0.87% Nickel alloyed ductile iron after boronizing process. Specimens were boronized at 950° C for 6, 8 and 10 hours holding time before being cooled in the furnace. The microstructure and boride layer formed on the surface of substrates were observed under Olympus BX60 Optical Microscope. Vickers Micro Hardness Tester was also performed to determine the hardness of boride layers. Boride layer was formed by diffusion of the boron into the metal lattice at the surface which composed double phase of FeB and Fe2B with saw-tooth morphology. The results of this study indicated that the thickness of boride layers increased from 109.8μm at 6 hours to 195.4μm at 8 hours holding time before they crack at 10 hours. The hardness of the material surface also increased from 1535 HV to 1623 HV at 6 and 8 hours respectively. In conclusion, the microstructure, borides thickness and hardness of borides layer were depending on boronizing time while temperature kept constant.

Application of Laser Additive Enhancing Technology in the Field of Cutting Tools

2017 ◽  
Vol 872 ◽  
pp. 8-13
Author(s):  
Yuan Ren ◽  
Wen Tao Wang ◽  
Xin Qiang Ma ◽  
Wei Cheng
Keyword(s):  
Grain Boundary ◽  
Cutting Tools ◽  
Alloy Coating ◽  
Optical Microscope ◽  
Solid State Laser ◽  
Micro Hardness ◽  
Hard Phase ◽  
Hardness Tester ◽  
Scanning Electron ◽  
Steel Cutting

Fe62 alloy coating was fabricated on the surface of #45 steel cutting edges with 2kW all-solid-state laser and powder feeding device. The substrate and forming layer are characterized by optical microscope and scanning electron microscope for microstructure, and tested by micro-hardness tester for micro-hardness. The results show that the forming layer combined with the substrate metallurgically. The microstructure of substrate is eutectoid ferrite and pearlite. The microstructure of layer is uniform and compact, with hard precipitation. The content of Cr, the hard phase generated element, at the grain boundary, is higher than that of grain inside and many hard phases were generated at the grain boundary. Compared with the substrate, the micro-hardness of forming layer increases by about 2 times. All these results show that application of laser additive enhancing technology in the field of cutting tools has larger potential.

INFLUENCE OF THE SOLIDIFICATION PARAMETERS ON DENDRITIC MICROSTRUCTURES IN UNSTEADY-STATE DIRECTIONALLY SOLIDIFIED OF LEAD–ANTIMONY ALLOY

2010 ◽  
Vol 17 (05n06) ◽  
pp. 477-486 ◽  
Author(s):  
M. ŞAHIN ◽  
E. ÇADIRLI ◽  
H. KAYA
Keyword(s):  
Growth Rate ◽  
Primary Dendrite ◽  
Linear Regression Analysis ◽  
Theoretical Models ◽  
Directionally Solidified ◽  
Constant Growth Rate ◽  
Dendrite Arm Spacing ◽  
Primary Dendrite Arm Spacing ◽  
Microstructure Parameters ◽  
Solidification Parameters

Pb-9.3wt.%Sb alloy was directionally solidified upwards under argon atmosphere under the two conditions; with different temperature gradients, (G = 0.93–3.67 K/mm) at a constant growth rate (V = 17.50 μm/s) and with different growth rates (V = 8.30–497.00 μm/s) at a constant (G = 3.67 K/mm) in a Bridgman furnace. The dependence of characteristic microstructure parameters such as primary dendrite arm spacing (λ1), secondary dendrite arm spacing (λ2) and dendrite tip radius (R) on the growth rate (V) and the temperature gradient (G) were determined by using a linear regression analysis. A detailed analysis of microstructure were also made and compared with the theoretical models and similar experimental works on dendritic solidification in the literature.

The Effect of Al2O3 Concentration on Properties of Ni-W-P-Al2O3 Electroless Composite Coating

2012 ◽  
Vol 468-471 ◽  
pp. 1163-1166 ◽  
Author(s):  
Wan Chang Sun
Keyword(s):  
Corrosion Resistance ◽  
Composite Coating ◽  
Potentiodynamic Polarization ◽  
Steel Substrate ◽  
Optical Microscope ◽  
Micro Hardness ◽  
Plating Bath ◽  
Hardness Tester ◽  
Al2o3 Concentration ◽  
Plating Solution

Ni-W-P-Al2O3 electroless composite coating was successfully co-deposited on 45 steel substrate using electroless plating. Optical microscope (OM), micro-hardness tester and potentiodynamic polarization were used to analyze the morphology, micro-hardness and corrosion resistance of the composite coating. The effect of Al2O3 concentration in the plating solution on the micro-hardness and corrosion resistance of the composite coating was mainly discussed. The results show that Al2O3 particles co-deposit with Ni-W-P homogeneously. The micro-hardness and corrosion resistance of the coating are improved with the increasing of Al2O3 concentration in the plating bath, and then decrease at a high Al2O3 concentration.

Wear Resistance of Ion Implanting Tungsten Carbide on 65Mn Steel Used as Harrow Disk

2014 ◽  
Vol 1030-1032 ◽  
pp. 259-262 ◽  
Author(s):  
Hai Yang ◽  
Ren Bao Jiao ◽  
Shu Yang Wang
Keyword(s):  
Wear Resistance ◽  
Phase Composition ◽  
Tungsten Carbide ◽  
Sandy Soil ◽  
Surface Hardness ◽  
Working Life ◽  
Optical Microscope ◽  
Micro Hardness ◽  
Hardness Tester ◽  
Carbide Layer

To improve the harrow disk made of 65Mn steel working life, an ion implanting metal in order to obtain tungsten carbide treatment was proposed in this work. Microstructure and phase composition of 65Mn steel obtained by ion implanting tungsten carbide process were analyzed by optical microscope and XRD, respectively. The surface hardness was tested by microscopic hardness tester, and the wear resistant performance of the wear layer was tested by abrader abrasor. The results showed that the micro-hardness of ion implanting tungsten carbide layer can be reached 1100 HV0.2, higher than that of 65Mn steel, the thickness of tungsten carbide layer was 400μm, which greatly improve the wear resistance. Harrow disk after the ion implanting tungsten carbide exhibited the excellent wear resistance in the sandy soil, and its working life was more than twice the length of the genera treatment harrow disk.

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