Investigation of Mechanical Properties and Salt Spray Corrosion Test Parameters Optimization for AA8079 with Reinforcement of TiN + ZrO2

This work mainly focuses on increasing the mechanical strength and improving the corrosion resistance of an aluminum alloy hybrid matrix. The composites are prepared by the stir casting procedure. For this work, aluminum alloy 8079 is considered as a base material and titanium nitride and zirconium dioxide are utilized as reinforcement particles. Mechanical tests, such as the ultimate tensile strength, wear, salt spray corrosion test and microhardness test, are conducted effectively in the fabricated AA8079/TiN + ZrO2 composites. L9 OA statistical analysis is executed to optimize the process parameters of the mechanical and corrosion tests. ANOVA analysis defines the contribution and influence of each parameter. In the tensile and wear test, parameters are chosen as % of reinforcement (3%, 6% and 9%), stirring speed (500, 550 and 600 rpm) and stirring time (20, 25 and 30 min). Similarly, in the salt spray test and microhardness test, the selected parameters are: percentage of reinforcement (3%, 6% and 9%), pH value (3, 6 and 9), and hang time (24, 48 and 72 h). The percentage of reinforcement highly influenced the wear and microhardness test, while the stirring time parameter extremely influenced the ultimate tensile strength. From the corrosion test, the hang time influences the corrosion rate. The SEM analysis highly reveals the bonding of each reinforcement particle to the base material.

Laser Processing of Ni-Based Superalloy Surfaces Susceptible to Stress Concentration

Reliable and resilient constructions are basic for ensuring the safety of various structures. The superalloys are used as constructive materials due to their superb mechanical properties and endurance. However, even these materials can have certain areas where the stress concentration is higher than expected, such as drilling holes, which are common in various structures that need additional enhancement. Surface laser modifications of the areas surrounding the holes drilled in Nimonic 263 sheets are done by pulsed picosecond and nanosecond Nd:YAG laser irradiations with pulse durations of 170 ps and ≤8 ns, respectively. Following the laser surface treatment, the effectiveness of the enhancement was analyzed by the microhardness test and the deformation test. The results show that the deformation and stress values are decreased by 25−40 percent, showing the improvement in the resilience to deformation. The Vickers microhardness test results indicate an improvement in the Nimonic 263 microhardness. The dimensions of the microcracks are higher for the untreated material in comparison to the laser-treated material.

Characterization of Nb2O5-Ni Coating Prepared by DC Sputtering

The Nb2O5-Ni coating was processed using DC sputtering on structural steel and study characterization of composite coating SEM/EDS inspection indicated clearly perfect incorporation of Nb2O5 within the nickel rich. Increasing in surface roughness and decreasing in average diameters of particles were obtained for coated surface compared with uncoated surface from AFM analysis, in addition, microhardness test and thickness test showed that increasing of the hardness value to 163 HV for Nb2O5 - Ni composite coating compared to 132 HV for uncoated samples, the hardness for Ni coating also increasing to155 HV and the thickness for Nb2O5-Ni composite coatings increased significantly compared to uncoated samples.

Effect of target-substrate distance on thickness and hardness of carbon thin films on SKD11 steel using target material from battery carbon rods

Carbon thin films on SKD11 steel were deposited by 40 kHz frequency plasma sputtering technique using a waste of battery carbon rods in argon plasma, and their mechanical properties were investigated by various target-substrate distances (1 cm, 1.7 cm, 2 cm, and 2.4 cm). The power used is 340 watts, the vacuum time is 90 minutes, and the gas flow rate is 80 ml/minute. The deposition time of carbon in plasma sputtering is 120 minutes with the initial temperature (temperature during vacuum) of 28 oC and the final temperature (the temperature after plasma sputtering) is 300 oC. The hardness value of SKD11 steel deposited with carbon thin films on SKD11 with target-substrate distance was tested using the Vickers microhardness test. Testing the thickness of the carbon thin films on the SKD11 steel substrate was carried out using a Nikon type 59520 optical microscope. Qualitative analysis of the thickness of the carbon thin films on the SKD11 steel substrate at a scale of 20 μm is shown by an optical microscope. Qualitatively, the thin film at a distance of 1.7 cm looks the brightest and thickest than other distance variations. Based on the Vickers microhardness test and Nikon type 59520 optical microscope, at the distance of 1 cm to 1.7 cm, the average thickness and hardness increased from 10,724 μm (286.6 HV) to 13,332 μm (335.9 HV). Furthermore, at the variation of the distance from 1.7 cm to 2.4 cm, the average thickness and hardness continued to decrease from 13.332 μm (335.9 HV) to 7.257 μm (257.3 HV). The possibility of interrupting atoms colliding with argon atoms in inert conditions increases at a long distance, thus causing the deposition flux on the SKD11 steel substrate to decrease

Effective methods for evaluating the properties of polymer products

The application of the acoustic method and the Vickers microhardness test allow obtaining information on the effect of processing conditions on the morphological features and properties of products made of ultra-high molecular weight polyethylene.

The Effect of EDM Process on the Microstructure of CP-Titanium Grade 2 and AISI 316 L in Cardiovascular Stent Manufacturing

The aim of this research is to investigate the effect of the EDM process on the microstructure of CP-Titanium grade 2 and AISI 316 L in cardiovascular stent manufacturing. The microstructure was observed by an optical light microscope, and the microhardness test is conducted by microhardness vikers to validate the phase that is formed on the material. The pulse currents which were used in the manufacturing of stent by die sinking EDM were 1.5 A and 6.0 A. The experimental results show that the microstructure of CP-Titanium grade 2 is transformed after EDM in cardiovascular stent manufacturing, but it does not occur in the material AISI 316 L. The microstructure of CP titanium grade 2 is transformed from equiaxed α to be TiH for 1.5 A, and equiaxed α to be α’ martensite and TiH for the pulse current 6.0 A. The hardness of equiaxed α, α’ martensite, and TiH are 108 HVN, 113 HVN, and 254 HVN, respectively. The HAZ only occurs in the CP-Ti 2, and its depth for 1.5 A and 6.0 A are 45 μm and 73 μm, respectively.

Comparison of Microhardness and Compressive Strength of Alkasite and Conventional Restorative Materials

The aim of this study was to compare compressive strength and microhardness of recently introduced alkasite restorative materials with glass ionomer cement and flowable composite resin.For each material, 20 samples were prepared respectively for compressive strength and Vickers microhardness test. The compressive strength was measured with universal testing machine at crosshead speed of 1 mm/min. And microhardness was measured using Vickers Micro hardness testing machine under 500 g load and 10 seconds dwelling time at 1 hour, 1 day, 7 days, 14 days, 21 days and 35 days.The compressive strength was highest in composite resin, followed by alkasite, and glass ionomer cement. In microhardness test, composite resin, which had no change throughout experimental periods, showed highest microhardness in 1 hour, 1 day, and 7 days measurement. The glass ionomer cement showed increase in microhardness for 7 days and no difference was found with composite resin after 14 days measurement. For alkasite, maximum microhardness was measured on 14 days, but showed gradual decrease.

Effect of ceramic particles reinforcement on the ballistic resistance of friction stir processed thick AA6061 surface composite targets

In this paper, the effect of ceramic particles (Zirconium, Boron Carbide and Graphene) on the ballistic resistance of Friction Stir Processed (FSPed) thick AA6061 targets had been explored. The Base Metal AA6061 plates of 25 mm thickness were FSPed by reinforcing Zirconium (Zr), Boron Carbide (B4C) and Graphene (G), thus producing FSPed-Zr, FSPed-B4C and FSPed-G surface composite targets. Microhardness test was carried out and the hardness of FSPed-Zr, FSPed-B4C and FSPed-G were found to be 96, 106 and 122 HV respectively. High velocity ballistic experiments were conducted on all the targets against Ø7.62x51 mm Armour Piercing Projectile at an initial velocity of 680 ± 10 m/s. AA6063 backing plates were used to identify the ballistic resistance of the FSPed targets by Depth of Penetration (DOP) method. Consequently, higher microhardness along with frictional characteristics had increased the ballistic resistance of FSPed-G targets by 70.8%. Further, by analyzing the penetration channel, it was noticed that in FSPed-G target, the jacket detachment occurred in the entry region predominantly where the microhardness was the highest compared to other two regions. This phenomenon occurred just after the entry region for FSPed-B4C target and in middle region for FSPed-Zr target. Scanning Electron Microscopy (SEM) images inferred that, FSPed targets have absorbed maximum projectile’s kinetic energy at the entry region itself, resulting in formation of cracks. As a result, middle and exit region experienced less impact. Post ballistic microhardness test showed enhanced microhardness in the entry region of FSPed-G target due to severe work hardening. Hence the ceramic particles deposited by FSP have reduced the kinetic energy of the projectile with FSPed-G target resulting in maximum ballistic resistance.

PENGARUH VARIASI SUHU, KONSENTRASI LARUTAN ASAM SULFAT DAN ASAM OKSALAT PADA PROSES HARD ANODISASI TERHADAP KEKERASAN PERMUKAAN ALUMINIUM ALLOY 6061

Anodisasi merupakan suatu proses elektrokimia pada logam Aluminium dengan tujuan untuk memperoleh lapisan tipis Aluminium Oksida (Al2O3) yang sifatnya lebih baik dari pada logam Aluminium itu sendiri. Penelitian ini menitik beratkan pada proses anodisasi Aluminium yang menggunakan variasi larutan elektrolit campuran Asam Sulfat (H2SO4) dengan Asam Oksalat (H2O2C4). Dengan lamanya waktu 40 menit dengan rapat arus 3 Amp/dm² dan variasi suhu 5 ˚C, 10 ˚C, dan 15 ˚C. Terhadap karakteristik lapisan yang terbentuk setelah hasil anodisasi pengujian dilakukan dengan uji kekerasan permukan yaitu Microhardness Test dengan metode Microvickers. Dan hasil penelitian di dapat kekerasan permukaan tertinggi pada campuran Asam Sulfat 12 % dan Asam Oksalat 1 % pada suhu 5 ˚C sebesar 334.37 HVN, untuk Asam Sulfat 12 % dan Asam Oksalat 2 % pada suhu 5 ˚C sebesar 316.03 HVN, dan untuk Asam Sulfat 1 % dan Asam Oksalat 12 % pada suhu 5 ˚C tidak terjadi proses anodisasi.Kata kunci : Aluminium, Anodisasi, Larutan Elektrolit, Suhu, Microvickers.