Effect of Atomization Parameters on Size and Morphology of Al-17Si Alloy Powder Produced by Free Fall Atomizer

Abstract: In the present work the effect of process parameters on the characteristics of Al-17Si alloy powder produced by gas atomization using a free fall nozzle of different apex angles. The axial gas velocity away from the nozzle exit is measured for different operating pressures. The alloy was melted to a superheat temperature of 100, 150 and 200°C and atomized by varying the gas flow rate and melt flow rate. The powder produced during gas atomization process generally exhibits a wide size distribution. ASTM standard sieve with vibratory shaker is used for powder analysis. The characterization of powder particles was accomplished by the parameters such as mass median, average size of powder particles; standard deviation and morphology of powder were studied by scanning electron microscopy. It is observed that decrease of apex angle results in axial velocity decreases in entire applied gas pressures range. Increase in apex angle results in decrease of gas jet length to metal stream collision, the median particle diameter of the powder increases resulting in decrease in particle irregularity. The median particle diameter of the powder has been shown to decrease almost linearly with increase in gas to melt flow (G/M) ratio. The sauter mean diameter variation, however, decreases slowly with increase in G/M ratio. Median particle diameter is significantly reduced with increase in the melt superheat

Microstructures and Mechanical properties of Spray deposited and Heat-treated Al-25Mg2 Si-2Cu alloy

The microstructural characteristics and  mechanical properties of Al–25Mg2Si-2Cu alloy were investigated. The alloy produced by spray atomization and deposition techniques followed by hot compression(HC) and age hardening(AGH) at 180ºC for 2h and 2h  intervals after the solution heat treatment. The microstructure features of as cast, spray deposited (SD),hot compressed and heat-treated alloys were studied. the results show the microstructure of spray-deposited alloy mainly comprised of a uniform distribution of   intermettalics   ?-Mg2Si phase, ?- Al2Cu and Q phase in Al-matrix. Eliminating the porosity of deposit and fragmentation of the ? And Q phases is the main features during hot compression. After solution treating and age hardening, the microstructure found to be comprised of mainly Mg2Si phase in a fine spherical form. Large quantity of ?- Al2Cu phase and Q Phase less than 50 nm in size uniformly distributed in the Al- matrix during aging. These fine ? particles combined with the ? can significantly increase the tensile strength and hardness of the alloy. In the peak-aged condition is because of high concentration of Mg2Si and Al2Cu metastable phases. The microstructural features of alloys been investigated through Optical (OM) and Scanning electron microscopy (SEM) and analyses of phases were carried out using Energy dispersive X-ray( EDS).The improvement in the tensile and hardness properties of studied alloys was investigated by tensile test and  micro- hardness.Keywords: Al-Mg2Si alloy, Spray deposition, Age hardening, Microstructure, Mechanical properties, Micro hardness

Influence of cu addition on the wear behavior of a eutectic Al–12.6Si alloy developed by the spray forming method

first_pagesettingsOrder Article Reprints Open AccessArticle Influence of Cu Addition on the Wear Behavior of a Eutectic Al–12.6Si Alloy Developed by the Spray Forming Method by Dayanand M. Goudar 1,Julfikar Haider 2ORCID,K. Raju 3,Rajashekar V. Kurahatti 4 andDeesy G. Pinto 5,6,* 1 Department of Mechanical Engineering, Tontadarya College of Engineering, Gadag 582101, India 2 Department of Engineering, Manchester Metropolitan University, Manchester M15GD, UK 3 Department of Mechanical Engineering, St. Joseph Engineering College, Mangaluru 575028, India 4 Department of Mechanical Engineering, Basaveshwar Engineering College, Bagalkot 587101, India 5 Department of Civil Engineering and Geology, University of Madeira, Campus da Penteada, 9020-105 Funchal, Portugal 6 CQM-Centro de Química da Madeira, University of Madeira, Campus da Penteada, 9020-105 Funchal, Portugal * Author to whom correspondence should be addressed. J. Compos. Sci. 2024, 8(3), 88; https://doi.org/10.3390/jcs8030088 Submission received: 19 January 2024 / Revised: 9 February 2024 / Accepted: 23 February 2024 / Published: 27 February 2024 (This article belongs to the Special Issue Metal Composites, Volume II) Downloadkeyboard_arrow_down Browse Figures Versions Notes Abstract In the present study, the influence of the addition of copper (Cu) on the wear behavior of a Al-12.6Si eutectic alloy developed using the spray forming (SF) method was discussed, and the results were compared with those of as-cast (AC) alloys. The microstructural features of the alloys were examined using both optical and the scanning electron microscopy, and the chemical composition and phase identification were achieved by X-ray diffraction (XRD) analysis. The results revealed that the microstructure of binary the SF alloy consisted of fine primary and eutectic Si phases, evenly distributed in the equiaxed α-Al matrix, whereas the Cu-based SF ternary alloy consisted of uniformly distributed fine eutectic Si particulates and spherical-shaped θ-Al2Cu precipitates, uniformly distributed in α-Al matrix. In contrast, the AC ternary (Al-12.6Si-2Cu) alloy consisted of unevenly dispersed eutectic Si needles and the coarse intermetallic compound θ-Al2Cu in the α-Al matrix. The addition of Cu enhanced the micro hardness of the SF ternary alloy by 8, 34, and 41% compared to that of the SF binary, AC ternary, and binary alloys, respectively. The wear test was conducted using a pin-on-disc wear testing machine at different loads (10–40 N) and sliding velocities (1–3 ms−1). The wear tests revealed that SF alloys exhibited an improved wear behavior in the entire applied load and sliding velocity range in comparison to that of the AC alloys. At a load of 40 N and a sliding velocity of 1 ms−1, the wear rate of the SF2 alloy is 62, 47, and 23% lower than that of the AC1, AC2, and SF1 alloys, respectively. Similarly, at a sliding velocity of 3 ms−1, the wear rate of the SF2 alloy is 52%, 42%, and 21% lower than that of the AC1, AC2, and SF1 alloys, respectively. The low wear rate in the SF2 alloy was due to the microstructural modification during spray forming, the precipitation of fine Al2Cu intermetallic compounds, and increased solid solubility. The SF alloys show an increased transition from oxidative to abrasive wear, while the AC alloys demonstrate wear mechanisms that change from oxidative to abrasive, including delamination, with an increase in sliding velocity and load

Investigation of the influence of Ni and Cu additions on the wear behavior of spray formed Al-15Si alloy at elevated temperature

The aim of this study is to develop a novel class of alloy material using spray forming process, which is a rapid solidification process that produces refined, equiaxed microstructures with low segregation. In the present study, the effects of adding Ni and Cu on the dry sliding wear behavior of the spray formed Al-15Si alloy at different elevated temperatures were investigated and compared with the cast Al-15Si alloy. Al-15Si and Al-15Si-4Ni-2Cu alloys were prepared by spray forming and conventional casting methods. The microstructure of the alloys was examined using optical and scanning electron microscopy (SEM) and energy dispersive X-rays. The hardness was measured using a Vickers hardness tester. Dry sliding wear tests at room temperature, 25 °C, 100 °C, 200 °C, and 300 °C were performed on a pin-on-disc tribometer at different loads (10, 20, 30, 40, 50 N) and a sliding velocity of 1.0 m/s. The microstructure of the spray-formed Al-15Si-4Ni-2Cualloy show fine, spherical form of primary Si, eutectic Si phases and fine dispersion of intermetallic particles. The spray-formed alloys display higher hardness values compared to the cast alloys and the spray formed Al-15Si-4Ni-2Cu alloy show a hardness almost 24% higher than the spray formed binary alloy. Lower wear rate and coefficient of friction were obtained in the Al-15Si-4Ni-2Cu alloy at all the normal loads and elevated temperatures. The spray formed alloys emerge as a better wear resistant material than the cast alloys at elevated temperatures. Although oxidative, abrasive and delamination wear mechanisms were found in the alloys manufactured by both the technique but severe plastic deformation was observed only in the cast alloys

Microstructural, Mechanical and Wear behavior of in-situ Al-TiB2 composites

In this study, mechanical and wear properties of in-situ stir cast Al-TiB2 composites were investigated. The composites were prepared by a metal salt reaction with different (3.0, 5.0 and 7.0 wt %) TiB2 contents. The microstructure of the composites were examined through an optical and scanning electron microscopy (SEM/EDS). The microstructures clearly revealed the uniform distribution of TiB2 particles in the Al matrix. The hardness of the in-situ Al-TiB2 based composites increased by 42%, 55%, and 58% compared to the matrix with the addition of 3, 5, and 7 wt% TiB2 reinforcements, respectively. The tensile strength of the 3, 5, and 7 wt% TiB2 stir-cast composites increased by 25%, 33%, and 45%, respectively, compared to the matrix, whereas the ductility decreased by 4.9%, 24.3%, and 41.3%, respectively. A pin-on-disk tester was used to perform a dry sliding wear test at different loads and sliding speeds. In comparison to the Al matrix, the composite materials showed improved wear resistance. Furthermore, in the entire applied loads and sliding velocities, the wear rate decreased with the increase in TiB2 content. The composites displayed lower wear rates due to their high hardness and strong interfacial bonding between the in-situ reinforcement and the matrix alloy

Microstructural features and mechanical properties of spray -formed hypereutectic Al-Si-Ti alloy

In the present study, the effect of the addition of Ti on the microstructural and mechanical properties of hypereutectic (Al/15 wt. %Si) spray-formed (SF) alloys has been investigated and compared with as-cast (AC) alloys. Al/15Si and Al/15Si/2Ti alloys were synthesised by spray forming method. The microstructural features of the alloys were explored under an optical microscope, and a scanning electron microscope (SEM) and X-ray diffraction (XRD) analysis were carried out for phase identification. The phase analysis confirmed the presence of α-Al and Si phases in all the alloys, with additional peaks attributed to Al3Ti and AlSi2Ti present in the Al/15Si/2Ti alloys. The microstructure of the SF1 alloy (Al/15Si) consisted of globular, fine Si phases (primary and eutectic) distributed homogeneously in the equiaxed Al matrix. The addition of Ti to the binary SF1 alloy led to the formation of an SF2 alloy (Al/15Si/2Ti) with a fine intermetallic phase of Al3Ti and further spheroidisation of Si particles. The SF1 and SF2 alloys exhibited 30% and 40% greater microhardness, respectively, than did their corresponding AC alloys. With the addition of Ti, the ultimate tensile strength of the SF2 alloy increased by 19% compared to that of the SF1 alloy. Furthermore, a significant increase in yield strength and ductility was observed in the SF alloys compared to the AC alloys. Adding Ti to hypereutectic Al/15Si alloy via the spray-forming method provides a better alternative material for aerospace and automotive applications

Applying multi-response optimization for sustainable machining of 316 stainless steel with coconut oil assisted minimum quantity lubrication

Environmental machining was investigated using coconut oil and minimal quantity lubrication (MQL) in the turning of AISI 316 stainless steel. The turning parameters and MQL flow rate were optimized using ANOM and ANOVA in multi-response analysis to produce the best hardness and minimum surface roughness in the machined surface of AISI 316 stainless steel. The feed, speed, depth of cut, and MQL flow rate during turning were used as the input parameters and surface roughness and hardness as the output parameters. The experimental plan was developed using Taguchi's L9 orthogonal array. It was found that minimum surface roughness (Ra: 1.12 µm and Rz: 6.37 µm) was achieved at a cutting speed of 120 m/min, feed rate between 0.25 to 0.3 mm/rev, the depth of cut between 1.0 to 1.5 mm and a MQL flow rate of 90 ml/hr. Micro hardness was measured from the machined surface to a depth of 1.075 mm to determine the machining affected zone (MAZ). It has been noted that the hardness reduced with an increase in machined surface depth. The MQL with coconut oil was shown to be an ecofriendly lubrication method for machining difficult-to-cut materials like stainless steel and keeping good surface integrity

Effects of thermal ageing on the wear behavior of the cerium modified Al-18si-3.6cu alloy

In the present investigation, an Al-18Si-3.6Cu alloy was modified by cerium (Ce), heat treated (T6), and aged for 1, 3, 5, and 7 h at 210°C. The resulting microstructures revealed that the addition of Ce as a modifier changed the morphology of the primary Si from coarse with a sharp edge to spherical, large-acicular/needle-like eutectic Si into a fibrous state, and dendrites of the Al phase into round branches with less interface separation. After thermal ageing, the microstructure of the modified alloy revealed no change in the morphology of the primary Si phase. However, a considerable change in the eutectic Si phase and the formation of fine precipitates of Al2Cu and Al2CeSi intermetallics in the matrix. Hardness was found to be significantly higher in the modified and age-hardened alloys. A Pin-on-disc wear tester was used to investigate the dry sliding wear behavior of alloys at different loads (10, 20, 30, and 40 N) and 1.0 m/s sliding velocity. The results indicated that the wear rate in the modified alloy was lower than the base alloy. Furthermore, the modified alloy after 5 h age hardening demonstrated high wear resistance and improved wear bearing capacity compared to the 1, 3, and 7 h age hardened alloys

Evaluating Comparative Wear Behaviour of Al-15%Si Based Alloy/Composites Reinforced with Zinc and Zirconium Oxide

The demand for high performance alloy/metal matrix composite has increased for the applications where a relative motion between two bodies is dominant. In the present study, tribological characteristics of Al- 2 15%Si based alloy/composites reinforced with 10%Zn and 15%ZrO2 were investigated. Binary Al-15%Si alloy and Al-15%Si-10%Zn base matrix alloy were prepared by melting commercially pure Al, Si and Zn whereas Al-15%Si-10%Zn-15%ZrO2 composite was manufactured by the stir casting method. The dry sliding wear test was conducted in a Pin-on-Disc tester under different sliding velocities and loading conditions. Optical microscope and scanning electron microscope (SEM) with EDS were used for metallographic and wear behaviour analysis. The microstructure of the binary alloy consisted of block-like coarse primary Si and needle type eutectic Si phases randomly distributed in the α-Al dendrites. The microstructural examination of the ZrO2 reinforced Al-15%Si-10%Zn based composite revealed primary globular Si with a size between 25 µm to 75 µm; fragmented rod like eutectic Si phase and uniform dispersion of ZrO2 particles in aluminum. The results showed a reduction infriction coefficient and substantial enhancement in the hardness and wear resistance of the composite compared to the binary and base matrix alloys. The superior wear resistance could be due to a combined effect of solid lubrication provided by Zn and high fracture toughness and wear resistance by the ZrO2 particles. The predominant oxidative and abrasive wear were identified as the mechanisms that led to the material failure by the plastic deformation, and delamination