Papers by Keyword: Powder Metallurgy

Abstract: On the one hand, cermet has the advantages of metal materials, and on the other hand, it maintains the excellent properties of ceramic materials, and is a very important new engineering material. In this paper, the alumina/aluminum cermet material composite powder was prepared by ball milling, and its densification properties were characterized and studied to provide reference for the preparation of high-performance cermet materials. When the ball milling time is more than 6h, the distribution of alumina particles around the aluminum powder is relatively uniform. The research shows that: with the extension of the ball milling time, the number of pinning of Al₂O₃ particles on the surface of the Al ball first increases and then decreases; The trend of decreasing; with the increase of ball-to-powder ratio, the distribution of Al₂O₃ particles on the surface of Al balls is more uniform. Considering its cost-effectiveness, it is more suitable to prepare pinned alumina/aluminum-ceramic composite powder under the conditions of ball milling speed of 360r/min, ball-to-material ratio of 2:1 and ball milling time of 12h. When the Al content gradually decreased, the density and hardness of the cermet material also decreased gradually. When the Al content gradually decreased, the density and hardness of the cermet material also decreased gradually. When Al accounts for 75% in the sample, the microstructure is dense and the hardness is higher. When the molding pressure is 20MPa, the unevenness of the surface of the material is greatly relieved, relatively flat, and the densification effect is better. When the sintering temperature is 800°C, the fired sample is very dense, and the particles have relatively high bonding strength, but a small amount of aluminum is precipitated on the surface of the sample, forming a silver-white spherical substance.

Abstract: The crucial manufacturing process in powder metallurgy (PM) is the mixing process. This process ensures blending sufficiently to achieve a uniform and consistent product. Various mixing parameters provide an impact on product properties and fluency during the mixing process. The mixing speed is the most considered parameter which affects the homogeneity and properties of the PM product. The powder of 89,95% wt Cu and 10%wt Sn was mixed at 14, 22, 30, 38 rpm respectively for 120 minutes using a double cone mixer to obtain homogeneity pow-der mixture at 40% filling rate mixer. The mixed powder was compacted at 700 MPa in the 4-column compacting machine. Green compact product was sintered at 200°C for 20 minutes. Sintered specimens were investigated on densification and hardness test. The microstructure was investigated by SEM/EDX and X-ray diffraction. The result showed that the Cu particle form to flake shape, while the Sn particle tends to form irregular rod-like. Particle size on Cu-Sn composite most being finer along with increasing mixing speed. Homogenously distributed dispersed Cu and Sn particles can be achieved successfully at 30 rpm. Furthermore, the hardness test value was 94,2 HRF. The density was 7,45 g/cm3 and the porosity was 15,19% Particle size decrease to 4.517 μm with increasing mixing speed.

Abstract: Powder metallurgy (PM) is an alternative approach to ingot metallurgy (IM) in the production of metal products. It is of paramount importance for PM to be able to produce fully dense products for it to make headway in becoming an equal alternative to IM and be a better option economy-wise. Cold rolling is an inexpensive post-sintering densification option that enables the lowering of sintering conditions. Experiments were carried out in this study to investigate cold rolling parameters on the densification of titanium brown compacts with a starting relative density of 89.3 %. The highest relative density obtained during the cold rolling experiments was 97.7 % without any annealing. It was found that the density increases with an increase in the percentage reduction of cold rolling. High percentage reductions reduce the number of roll passes needed to increase the density up to a limit where the brown compacts become susceptible to severe rolling defects. It was also found that the total increase in density increases with a decrease in cold rolling speed. An increase in the relative density of 8.36 % was observed at the cold rolling speed of 1 rpm, whereas the highest increase recorded at 10 rpm was 5.83 %.

Abstract: In this study, porous binary Ti-(x)Zr alloys of nominal Zr contents (x=10, 20 and 30 at. %) with differing porosities were manufactured, using powder metallurgy with compaction conducted under a pressure of 300MPa and sintering at 1200 °C for 6 h. A space holder agent was employed to control the general porosity. The microstructures were characterized by scanning electron microscopy and energy dispersed spectroscopy. The phase constitution was done by X-ray diffractometer. Uniaxial compressive tests were performed to determine the mechanical behaviors. Microstructural studies revealed macro/micro pores generated were mostly irregularly shaped with a uniform pore size distribution in all Ti-(x)Zr (at. %) alloys. The finer microstructure was obtained with increasing Zr contents. The mechanical performances of the porous Ti-(x)Zr (at. %) binary systems were strongly influenced by Zr and general porosity.

Abstract: Al-Zn-based AMC is a light metal, with low density, excellent mechanical and mechanical properties, suitable for use in automotive, electrical, general-purpose electronics, machinery and equipment. However, the development of this alloy is limited by its low hardness and low corrosion resistance, which limits its use in many applications. This corrosion process can cause fitting corrosion and can damage the passive oxide layer that protects the metal from corrosion. This study aimed to increase the corrosion resistance of AMC Al-Zn by adding hydroxyapatite ceramic reinforcement from snail shells in a corrosive medium of 3.5% NaCl solution. The HAp is used as an AMC amplifier. AMC uses Al-Zn alloys with a ratio of 90% to 10% by mass. The variation of HAp enhancer used was 10, 15, 20, 30 and 40% by weight. This AMC was produced by powder metallurgy using 250 KPa compression for 20 min with sintering at 550°C for 2 h followed by slow cooling. The characterization of Al-Zn-based AMCs was performed by electrodynamic polarization testing in 3.5% NaCl solution. From the experimental results, the addition of HAp snail waste at a concentration of 20% by weight with matrix composition Al₉₀-Zn₁₀ is an AMC preparation with optimal corrosion resistance. The corrosion rate of Al₉₀-Zn₁₀/20HAp is 0.01 mmpy, while the corrosion rate of Al₉₀-Zn₁₀/0HAp is 1.15 mmpy. The addition of HAp up to 20% by weight showed the highest micro-hardness (117.90 Hv) while the smallest micro-hardness occurred at AMC Al₉₀-Zn₁₀/0HAp (87.57 Hv). The HAp material could very well be used as an AMC-reinforced biomaterial for biomedical applications.

Abstract: Nowadays, 316L stainless steel implant materials exhibit a promising position in the field of biomaterials application, especially in medical due to their higher strength compared to other ceramic base materials. Therefore, in this work, the production of 316L implant materials and examination of the mechanical characteristics were carried out. Powder Metallurgy process has been chosen to produce the implant materials due to its high advantages in demonstrating the high mechanical properties of the green sample. 316L stainless steel with zinc streate powder of three different compositions, i.e., the first of 99% 316L stainless steel and 1% zinc stearate, the second of 97% 316L stainless steel and 3% zinc streate, and the third of 95% 316L stainless steel and 5% zinc streate, were cold pressed individually at 600 MPa pressure using UTM and sintered the green samples at 1120 °C for 1 hour and 30 minutes. Sintering temperature and time were the same for all the specimens. We investigated the mechanical behaviour of 316L stainless steel implant materials of different compositions at the same temperature for the same duration of time. After that, the mechanical properties and densification of this material were investigated.

Abstract: Copper is a widely used material in various industries due to its properties like good corrosion resistance, thermal and electrical conductivity, stability at high temperatures, etc. To increase the mechanical and tribological properties, additional reinforcement should be added to the copper matrix. Adding tin into copper will result in the formation of bronze which is stronger and harder than either of the pure metals. This study deals with the comparative study of mechanical and tribological properties of microwave sintered and conventionally sintered Cu-6Sn. The mechanical properties of Cu-6Sn processed through powder metallurgy are compared with that of Cu-6Sn processed through casting. Hardness and wear resistance was observed to be higher for conventionally sintered specimens. Microwave sintered Cu-6Sn exhibit enhanced mechanical properties compared to Cu-6Sn processed through casting.

Abstract: A growing demand for advanced composite materials as well as diverse design requirements offering significant weight savings in comparison to conventional materials have all contributed to a growing interest in composite materials. This review paper is focused on Powder Metallurgy (P/M) process to fabricate magnesium based metal matrix composites. The excellent oxidation and corrosion resistance and low density of Silicon carbide have made it a popular material even at very high temperatures. Despite their very high specific strength, magnesium matrix composites possess excellent cast ability, good damping capabilities, and greater machinability. Therefore, this review paper discusses the importance, fabrication, and properties of magnesium matrix composite materials for industry applications. An examination of the properties of recently produced magnesium matrix composites by various researchers is presented in this review paper.

Abstract: This paper discusses Copper Metal Matrix Composites. It is obvious that copper matrix composites have been heavily relied upon by many industries because of their high wear resistance, corrosion resistance, excellent electrocatalytic properties, and high strength. The excellent electrical conductivity of copper-based materials also enables these materials to function as lubricants and anti-frictional materials. These materials were widely used in transportation, electrical contact transmission, and aerospace. Copper-based metal matrix composites have wide application due to their excellent mechanical, electrical, and thermal characteristics. Copper based metal matrix composites are also corrosion resistant and have a high strength. A contemporary study evaluated the effects of different parameters on powder metallurgy fabricated copper matrix metal composites. The focus was on understanding the applications and mechanical properties of copper-based composite materials.

Abstract: This scientific study deals with the main issues related to the process of filling inhomogeneous materials into a rectangular hopper. The article develops an algorithm for filling particles of structurally inhomogeneous materials. A micrograph of the structure of samples of inhomogeneous materials is presented. It was found that the structure of samples of heterogeneous materials consists of three layers: external, internal and impurities of various grinding aggregates. Based on microstructural analysis, the presence of particles of various shapes and sizes was justified. On the basis of which the main initial conditions for filling the package with spherical particles were described. The basic physical and mechanical properties of structurally inhomogeneous materials were studied using the obtained results. We also constructed an approximate dependence of porosity on the particle diameter of inhomogeneous materials.