scholarly journals Effect of Ball Size on the Microstructure and Morphology of Mg Powders Processed by High-Energy Ball Milling

Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1621
Author(s):  
Jesus Rios ◽  
Alex Restrepo ◽  
Alejandro Zuleta ◽  
Francisco Bolívar ◽  
Juan Castaño ◽  
...  

Commercial powders of pure magnesium were processed by high-energy ball milling. The microstructural and morphological evolution of the powders was studied using scanning electron microscopy (SEM), energy dispersive spectrometry (EDX) and X-ray diffraction (XRD). From the results obtained, it was determined that the ball size is the most influential milling parameter. This was because balls of 1 mm diameter were used after a previous stage of milling with larger balls (i.e., 10 and 3 mm). The powder particles presented an unusual morphology with respect to those observed in the Mg-milling literature and recrystallization phenomena. Moreover, the result strongly varied depending on the ball-to-powder weight ratio (BPR) used during the milling process.

2014 ◽  
Vol 802 ◽  
pp. 29-34
Author(s):  
Leandro Koji Kayano ◽  
Daniel Murusawa ◽  
Gilda Maria Cortez Pereira ◽  
Alfeu Saraiva Ramos

This work presents the results on the high-energy ball milling and hot pressing of Ni-48Ti-2Sn and Ni-45Ti-5Sn (at-%) powder mixtures. The milling process was performed in a planetary ball mill using stainless steel vial (225 mL) and hardened steel balls (19 mm diameter), rotary speed of 300 rpm, and a ball-to-powder weight ratio of 10:1. Samples were collected into the vial after different milling times: 60, 180 and 300 min. In the sequence, wet milling (isopropyl alcohol) was adopted up to 720 min in order to increase the powder yield into the vials. The as-milled and hot-pressed samples were characterized by X-ray diffraction, electron scanning microscopy, and energy dispersive spectrometry. Results indicated that the ductile particles were promptly cold-welded during the initial milling times. XRD patterns of the Ni-48Ti-2Sn powder mixture indicated that the peaks of Ni, Ti and Sn disappeared after milling for 3h. Following, peaks of NiTi and Ni4Ti3were preferentially formed during milling of Ni-Ti-Sn powders. A large amount of fine powders was yielded into the vial after wet milling for 720 min only. No significant carbon or oxygen contamination was detected by EDS analysis. Hot pressing produced homogeneous and dense samples which presented microstructures containing a large amount of the NiTi compound.


2012 ◽  
Vol 727-728 ◽  
pp. 233-238
Author(s):  
Gilda Maria Cortez Pereira ◽  
Marisa Aparecida de Souza ◽  
Tomaz Manabu Hashimoto ◽  
Vinicius André Rodrigues Henriques ◽  
Alfeu Saraiva Ramos

This work discusses on the preparation of Ni-45Ti-5Mo, Ni-40Ti-10Mo and Ni-46Ti-2Mo-2Zr (at-%) alloys by high-energy ball milling and hot pressing, which are potentially attractive for dental and medical applications. The milling process was performed in stainless steel balls (19mm diameter) and vials (225 mL) using a rotary speed of 300rpm and a ball-to-powder weight ratio of 10:1. Hot pressing under vacuum was performed in a BN-coated graphite crucible at 900°C for 1 h using a load of 20 MPa. The milled and hot-pressed materials were characterized by X-ray diffraction, electron scanning microscopy, and electron dispersive spectrometry. Peaks of B2-NiTi and Ni4Ti3were identified in XRD patterns of Ni-45Ti-5Mo, Ni-40Ti-10Mo and Ni-46Ti-2Mo-2Zr powders milled for 1h. The NiTi compound dissolved small Mo amounts lower than 4 at%, which were measured by EDS analysis. Moreover, it was identified the existence of an unknown Mo-rich phase in microstructures of the hot-pressed Ni-Ti-Mo alloys.


2020 ◽  
Vol 9 (4) ◽  
pp. e175943067
Author(s):  
João Augusto Martins Almeida ◽  
Bruna Horta Bastos Kuffner ◽  
Gilbert Silva ◽  
Patrícia Capellato ◽  
Daniela Sachs

There are a class of material widely used in bone tissue repair. This material is calcium phosphate ceramics (CPCs)that can be used on two phases: α and β. However, β-TCP is more used in bone regeneration than α–TCP due to the biocompatible and bioactive properties.In the present work evaluate the influence of these two distinct processes to deagglomeration and the consequence in the particle size of the β-TCP obtained through solid-state reaction. Among all of the routes used in research and industry to reduce the particles size of different materials, the high energy ball milling is one of the most effective, due to the high rotation speed that this process achieves. The deagglomeration through agate mortar is considered a cheaper process when compared with the high energy ball milling. The characterization of both powders, deagglomerated in high energy ball milling and agate mortar, was realized through scanning electron microscopy, to analyze the powder morphology, and laser granulometry, to determine the size of the particles. Also, the forerunner powder was previously submitted to x-ray diffraction to confirm the formation of the β-TCP phase. The analysis through x-ray diffraction confirmed that the phase formed during the calcination process corresponded to the β-TCP. The results obtained after the deagglomeration processes indicated that the morphology was predominantly irregular for both powders. In relation to the granulometry, the deagglomeration performed through agate mortar showed to produce particles with smaller size (11,4µm e 0,9µm) and heterogeneous distribution, while the high energy ball milling process produced particles with larger size (11,4µm a 1,8µm) and higher homogeneity.


2018 ◽  
Vol 930 ◽  
pp. 454-459
Author(s):  
Claudiney de Sales Pereira Mendonça ◽  
Vander Alkmin dos Santos Ribeiro ◽  
Mateus Morais Junqueira ◽  
Daniela Sachs ◽  
Leonardo Albergaria Oliveira ◽  
...  

Stainless steel components produced by powder metallurgy constitute an important and growing segment of the industry. The high energy ball milling process can be an alternative for the recycling of the stainless steel chips. A major advantage of stainless steel is its ability to be recyclable. The reuse of recyclable materials has as main objectives to minimize the environmental impacts and to rationalize the use of the energy chains. This work aims at the production of stainless steel, starting from machining chips pure, and with the addition of vanadium carbides by high energy planetary milling with ball to powder weight ratio 20:1, and mill speed of 350 rpm milled in argon atmosphere for 50h. The compaction of stainless steel samples with vanadium carbide was made in a cylindrical matrix at a pressure of 700 Mpa. The sintering process was performed in a vacuum atmosphere furnace at a temperature of 1200 ° C for 1h. Through the milling process with the addition of carbide it was possible to produce stainless steel powder with a mean particle size of 49 μm. By X-ray diffraction was observed the appearance of the ferritic, austenitic phase and the martensitic phase induced by deformation phase that remained even after the sintering. The density of the sintered material is around 77% of the melt, and the obtained porosity was low.


2012 ◽  
Vol 727-728 ◽  
pp. 1193-1198 ◽  
Author(s):  
Pietro Carelli Reis de Oliveira Caltabiano ◽  
Marisa Aparecida de Souza ◽  
Rodrigo Fernando Costa Marques ◽  
Maria Gabriela Nogueira Campos ◽  
Luis Rogério de Oliveira Hein ◽  
...  

The present work reports on the preparation of Al2O3-TiO2 ceramics by high-energy ball milling and sintering, varying the molar fraction in 1:1 and 3:1. The powder mixtures were processed in a planetary Fritsch P-5 ball mill using silicon nitride balls (10 mm diameter) and vials (225 mL), rotary speed of 250 rpm and a ball-to-powder weight ratio of 5:1. Samples were collected into the vial after different milling times. The milled powders were uniaxially compacted and sintered at 1300 and 1500°C for 4h. The milled and sintered materials were characterized by X-ray diffraction and electron scanning microscopy (SEM). Results indicated that the intensity of Al2O3 and TiO2 peaks were reduced for longer milling times, suggesting that nanosized particles can be achieved. The densification of Al2O3-TiO2 ceramics was higher than 98% over the relative density in samples sintered at 1500°C for 4h, which presented the formation of Al2TiO5.


2014 ◽  
Vol 802 ◽  
pp. 20-24 ◽  
Author(s):  
Lucas Moreira Ferreira ◽  
Luciano Braga Alkmin ◽  
Érika C.T. Ramos ◽  
Carlos Angelo Nunes ◽  
Alfeu Saraiva Ramos

The milling process of elemental Ti-2Ta-22Si-11B and Ti-6Ta-22Si-11B (at-%) powder mixtures were performed in a planetary Fritsch P-5 ball mill using stainless steel vials (225 mL) and hardened steel balls (19 mm diameter). Ball-to-powder weight ratio of 10:1 and a rotary speed of 300 rpm were adopted, varying the milling time. Wet milling (isopropyl alcohol) for 20 more minutes was used to increase the yield powder in to the vial. Following the Ti-Ta-Si-B powders milled for 600 min were heat-treated at 1100°C for 1 h in order to obtain the equilibrium structures. The milled powders and heat-treated samples were characterized by X-ray diffraction, scanning electron microscopy, and energy dispersive spectrometry. Supersaturated Ti solid solutions were formed during ball milling of Ti-Ta-Si-B powders while that the Ti5Si3 phase was formed after milling for 620 min of the Ta-richer powder mixture only. The particles sizes were initially increased during the initial milling times, and the wet milling provided the yield powder into the vials. A large amount of pores was found in both the sintered samples which presented the formation of the TiSS,(ss-solid solution) Ti6Si2B and TiB.


2017 ◽  
Vol 899 ◽  
pp. 19-24
Author(s):  
Lucas Moreira Ferreira ◽  
Stephania Capellari Rezende ◽  
Antonio Augusto Araújo Pinto da Silva ◽  
Gael Yves Poirier ◽  
Gilberto Carvalho Coelho ◽  
...  

The present work reports on the microstructure and oxidation resistance of Ni-25Nb, Ni-20Nb-5Ta and Ni-15Nb-10Ta alloys produced by high-energy ball milling and subsequent sintering. The sintered samples were characterized by optical microscopy, scanning electron microscopy, X-ray diffraction, energy dispersive spectrometry, and static oxidation tests. Homogeneous microstructures of the binary and ternary alloys indicated the major presence of the β-Ni3Nb compound as matrix, which dissolved large amounts of tantalum. Consequently, the β-Ni3Nb peaks moved toward the direction of smaller diffraction angles. Iron contamination lower than 6.7 at.-% was detected by EDS analysis, which were picked-up during the previous ball milling process. After the static oxidation tests (1100°C for 4 h) the sintered Ni-25Nb, Ni-20Nb-5Ta and Ni-15Nb-10Ta alloys presented mass gains of 31.5%, 30.5% and 28.8%, respectively. Despite the higher densification of the Ni-15Nb-10Ta alloy, the results suggested that the tantalum addition contributed to improve the oxidation resistance of the β-Ni3Nb compound.


2006 ◽  
Vol 54 (1) ◽  
pp. 93-97 ◽  
Author(s):  
J.L. Li ◽  
L.J. Wang ◽  
G.Z. Bai ◽  
W. Jiang

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