scholarly journals Influence of aluminium content on the microstructure and densification of spark plasma sintered nickel aluminium bronze

2021 ◽  
Vol 8 ◽  
pp. 9
Author(s):  
Avwerosuoghene Moses Okoro ◽  
Senzeni Sipho Lephuthing ◽  
Samuel Ranti Oke ◽  
Peter Apata Olubambi
Keyword(s):  
Spark Plasma Sintering ◽  
Ball Mill ◽  
Aluminium Content ◽  
Dry Milling ◽  
Plasma Sintering ◽  
Aluminium Bronze ◽  
Spark Plasma ◽  
Rate Of Heating ◽  
Compressive Pressure ◽  
Sintered Alloys

In this study, nickel aluminium bronze alloys (NAB) with appreciable densification and improved microhardness was consolidated via spark plasma sintering technique. The NAB alloy was synthesized from starting elemental powders comprised nickel (4 wt.%), aluminium (6, 8 & 10 wt.%) and copper using dry milling technique. Starting powders were homogeneously milled using gentle ball mill for 8 h at a speed of 150 rpm and a BPR of 10:1. Subsequently, the milled powders were consolidated using the spark plasma sintering technique at 750 °C under a compressive pressure of 50 MPa and rate of heating (100 °C/min). Furthermore, the powders and sintered alloys were characterized using SEM and XRD to ascertain the microstructural and phase evolutions during the synthesis of the NAB. The density and microhardness of the alloys were further investigated to ascertain the integrity of the sintered alloys. The results indicated that the increase in aluminium content resulted in the formation of intermetallic and beta phases on the alloy after sintering and the microhardness of the alloys improved with the increase in aluminium content.

Production of Dispersion-Strengthened Cu-TiB2 Alloys by Ball-Milling and Spark-Plasma Sintering

2007 ◽  
Vol 534-536 ◽  
pp. 1489-1492 ◽  
Author(s):  
Dae Hwan Kwon ◽  
Jong Won Kum ◽  
Thuy Dang Nguyen ◽  
Dina V. Dudina ◽  
Pyuck Pa Choi ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Ball Milling ◽  
Spark Plasma Sintering ◽  
Ball Mill ◽  
Milling Time ◽  
Rotation Speed ◽  
Sintering Temperature ◽  
Milled Powder ◽  
Plasma Sintering ◽  
Spark Plasma

Dispersion-strengthened copper with TiB2 was produced by ball-milling and spark plasma sintering (SPS).Ball-milling was performed at a rotation speed of 300rpm for 30 and 60min in Ar atmosphere by using a planetary ball mill (AGO-2). Spark-plasma sintering was carried out at 650°C for 5min under vacuum after mechanical alloying. The hardness of the specimens sintered using powder ball milled for 60min at 300rpm increased from 16.0 to 61.8 HRB than that of specimen using powder mixed with a turbular mixer, while the electrical conductivity varied from 93.40% to 83.34%IACS. In the case of milled powder, hardness increased as milling time increased, while the electrical conductivity decreased. On the other hand, hardness decreased with increasing sintering temperature, but the electrical conductiviey increased slightly

The Additives Influence on Heat-Conducting Properties of Aluminium Nitride Circuit Boards

2016 ◽  
Vol 712 ◽  
pp. 226-231
Author(s):  
A.S. Karakulov ◽  
N.V. Gusev ◽  
Yuriy Yu. Drozdov ◽  
N.Y. Nikonova
Keyword(s):  
Spark Plasma Sintering ◽  
Heat Conductivity ◽  
Ball Mill ◽  
Aluminium Nitride ◽  
Heat Conducting ◽  
Circuit Boards ◽  
Plasma Sintering ◽  
Nitride Ceramics ◽  
Spark Plasma ◽  
Conductive Properties

The paper presents the studies on evaluation of the influence of modified additives of Y2O3-, ZrO2- and Li2O3-type on heat-conductive properties of aluminium-nitride ceramics used as circuit boards. Sintering of the studied samples was carried out using AlN powders and the powders of the modifying additives, mixed in the ball mill based on the spark plasma sintering system “SPS”. Density and heat conductivity were measured for the obtained samples. It was ascertained that the most significant level of heat conductivity was obtained when using the additive mixture made of 7 wt. % of Li2O3 and 3wt. % of Y2O3, which reaches the level of 160 W/m·K. In addition, the results of the studies show that the addition of the modified powders leads to a significant increase of density; the additive consisting of 7wt.% of Li2O3 and 3wt.% of Y2O3 produces the greatest effect.

Properties of Ultrafine-Grained Tungsten Prepared by Ball Milling and Spark Plasma Sintering

2016 ◽  
Vol 821 ◽  
pp. 399-404 ◽  
Author(s):  
Monika Vilémová ◽  
Barbara Nevrlá ◽  
Zdenek Pala ◽  
Lenka Kocmanová ◽  
Marek Janata ◽  
...  
Keyword(s):  
Ball Milling ◽  
Spark Plasma Sintering ◽  
Ball Mill ◽  
Planetary Ball Mill ◽  
Coarse Grained ◽  
First Wall ◽  
Fine Grained ◽  
Plasma Sintering ◽  
Ultrafine Grained ◽  
Spark Plasma

Tungsten is currently considered as the most suitable plasma facing material for the first wall of a nuclear fusion reactor. First wall will be subjected to harsh conditions that will gradually deteriorate properties of the wall material. Some studies point out that fine-grained tungsten could be more resistant to the structure and property changes than coarse-grained tungsten. However, tailoring of tungsten microstructure is very laborious. Due to its high melting point, tungsten is very often processed mechanically and subsequently sintered into a compact body. In this study, preparation of ultrafine-grained tungsten by mechanical processing in a planetary ball mill was examined. Three types of tungsten samples were compared. One was made from coarse grained tungsten powder consolidated by SPS (spark plasma sintering). Other two samples were prepared from the powder processed in a planetary ball mill with and without addition of Y2O3. After ball milling, the powders were consolidated by SPS, i.e. fast sintering process that allows preserving fine-grained structure of the powder material. Properties of the samples such as hardness and thermal conductivity were examined and correlated with the processing history and microstructure.

scholarly journals Spark Plasma Sintering of Aluminum Nanocomposite Powders: Recent Strategy to Translate from Lab-Scale to Mass Production

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3372
Author(s):  
Roberto Hernández-Maya ◽  
Nicolás Antonio Ulloa-Castillo ◽  
Oscar Martínez-Romero ◽  
Emmanuel Segura-Cárdenas ◽  
Alex Elías-Zúñiga
Keyword(s):  
Electrical Conductivity ◽  
Spark Plasma Sintering ◽  
Mass Production ◽  
Ball Mill ◽  
Scale Up ◽  
Production Equipment ◽  
Multiwalled Carbon ◽  
Aluminum Powders ◽  
Plasma Sintering ◽  
Spark Plasma

The aim of this paper focuses on presenting a recent study that describes the fundamental steps needed to effectively scale-up from lab to mass production parts produced from Al powders reinforced with 0.5 wt% of industrial multiwalled carbon nanotubes (MWCNTs), with mechanical and electrical conductivity properties higher that those measured at the lab scale. The produced material samples were produced via a Spark Plasma Sintering (SPS) process using nanocomposite aluminum powders elaborated with a planetary ball-mill at the lab scale, and high-volume attrition milling equipment in combination with controlled atmosphere sinter hardening furnace equipment, which were used to consolidate the material at the industrial level. Surprisingly, the electrical conductivity and mechanical properties of the samples produced with the reinforced nanocomposite Al powders were made with mass production equipment and were similar or higher than those samples fabricated using metallic powders prepared with ball-mill lab equipment. Experimental measurements show that the hardness and the electrical conductivity properties of the samples fabricated with the mass production Al powders are 48% and 7.5% higher than those of the produced lab samples. This paper elucidates the steps that one needs to follow during the mass production process of reinforced aluminum powders to improve the physical properties of metallic samples consolidated via the SPS process.

scholarly journals Microstructure and Mechanical Properties of Ti-Nb Alloys Prepared by Mechanical Alloying and Spark Plasma Sintering

2019 ◽  
Vol 29 (3) ◽  
pp. 1445-1452 ◽  
Author(s):  
Damian Kalita ◽  
Łukasz Rogal ◽  
Tomasz Czeppe ◽  
Anna Wójcik ◽  
Aleksandra Kolano-Burian ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Mechanical Alloying ◽  
Spark Plasma Sintering ◽  
Recoverable Strain ◽  
Α Phase ◽  
Plasma Sintering ◽  
Nb Content ◽  
Spark Plasma ◽  
Sintered Alloys

Abstract The effect of Nb content on microstructure, mechanical properties and superelasticity was studied in Ti-Nb alloys fabricated by powder metallurgy route using mechanical alloying and spark plasma sintering. In the microstructure of the as-sintered materials, undissolved Nb particles as well as precipitations of α-phase at grain boundaries of β-grains were observed. In order to improve the homogeneity of the materials, additional heat treatment at 1250 °C for 24 h was performed. As a result, Nb particles were dissolved in the matrix and the amount of α-phase was reduced to 0.5 vol.%. Yield strength of the as-sintered alloys decreased with Nb content from 949 MPa for Ti-14Nb to 656 MPa for Ti-26Nb, as a result of the decreasing amount of α-phase precipitations. Heat treatment did not have a significant effect on mechanical properties of the alloys. A maximum recoverable strain of 3% was obtained for heat-treated Ti-14Nb, for which As and Af temperatures were − 12.4 and 2.2 °C, respectively.

Phase Analyses of a TtPt Alloy Synthesized by Spark Plasma Sintering

2011 ◽  
Vol 675-677 ◽  
pp. 1143-1146
Author(s):  
Hilda Kundai Chikwanda ◽  
Yoko Yamabe-Mitarai ◽  
Silethelwe Chikosha
Keyword(s):  
High Temperature ◽  
Spark Plasma Sintering ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Mechanically Alloyed ◽  
Plasma Sintering ◽  
High Temperature Xrd ◽  
Pt Alloy ◽  
Spark Plasma ◽  
Sintered Alloys

A Ti-50at%Pt alloy synthesized using the spark plasma sintering (SPS) technique has been characterized for phases’ identification. TiPt alloys have potential use as high temperature shape memory alloys(HTSMAs). Test specimens were prepared at SPS temperature of 1300°C. Sintering pressure and time were varied. The microstructural features of the specimens were investigated using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The electron microscope used was equipped with an EDS detector, that, together with the XRD, were used for both the identification and analyses of the phases in the starting materials and the sintered alloys. High temperature XRD (800 -1300°C) as well as ambient temperature XRD analyses were done on the starting mechanically alloyed powders. All the samples tested at elevated temperatures were subsequently tested at room temperature after cooling. XRD analyses of the sintered samples were all done at room temperature. Analyses of the XRD results revealed new distinct phases from a temperature of 1000°C. A comparison of the room temperature XRD results for alloy powders and that of the sintered alloys was made. The following phases have been identified and studied TiPt B2, TiPt B19, Pt3Ti, Ti3Pt and Pt5Ti3. SPS pressure and sintering time did not show much effect on the phases detected. The alloy composition was found to be very inhomogeneous.

Microstructure and Sintering Behaviors of Al–Cr–xSi (at.%) System Alloys Processed by Spark Plasma Sintering

2021 ◽  
Vol 21 (9) ◽  
pp. 4768-4772
Author(s):  
Yong-Ho Kim ◽  
Hyo-Sang Yoo ◽  
Hyeon-Taek Son
Keyword(s):  
Electron Microscopy ◽  
Spark Plasma Sintering ◽  
Hardness Tester ◽  
Plasma Sintering ◽  
Transmission Electron ◽  
Fine Microstructure ◽  
Spark Plasma ◽  
Si Content ◽  
Ar Gas ◽  
Sintered Alloys

In this study, microstructure and sintering behaviors of the gas-atomized Al-(25 or 30) Cr–xSi alloy (x = 5, 10 and 20 at.%) during spark plasma sintering (SPS) process were investigated. Gas-atomized alloy powders were manufactured using Ar gas atomizer process. These alloy powders were consolidated using SPS process at different temperature under pressure 60 MPa in vacuum. Microstructures of the gas-atomized powders and sintered alloys were analyzed using scanning electron microscopy (SEM) with energy–dispersive X-ray spectrometer (EDS), and transmission electron microscopy (TEM). Hardness of the SPS sintered alloys was measured using micro Vickers hardness tester. The Al–Cr–Si bulks with high Cr and Si content were produced successfully using SPS sintering process without crack and obtained fully dense specimens close to nearly 100% T. D. (Theoretical Density). The maximum values of the hardness were 834 Hv for the sintered specimen of the gas atomized Al–30Cr–20Si alloy. Enhancement of hardness value was resulted from the formation of the multi-intermetallic compound with the hard and thermally stable phases and fine microstructure by the addition of high Cr and Si.

scholarly journals The Glassy Structure Formation and Phase Evolution in Mechanically Alloyed and Spark Plasma-Sintered Al-TM-RE Alloys

2019 ◽  
Vol 28 (12) ◽  
pp. 7407-7418
Author(s):  
Ram S. Maurya ◽  
Tapas Laha
Keyword(s):  
Spark Plasma Sintering ◽  
Phase Evolution ◽  
Amorphous Structure ◽  
X Ray Diffraction ◽  
Mechanically Alloyed ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Xrd Patterns ◽  
Sintered Alloys ◽  
The Comparative Study

AbstractThe present study deals with the comparative study of amorphization tendency of Al86Ni6Y6, Al86Ni6Y6Co2 and Al86Ni6Y4.5Co2La1.5 alloy powders via mechanical alloying performed at 300 revolution per minute with ball-to-powder ratio of 15:1 and subsequently the devitrification tendency of 300 °C and 500 °C spark plasma-sintered bulk amorphous alloys. Mechanically alloyed Al86Ni6Y6, Al86Ni6Y6Co2 and Al86Ni6Y4.5Co2La1.5 powders yielded nearly fully amorphous structure after 140, 170 and 200 h, respectively. The requirement of prolonged milling was attributed to the soft and ductile nature of aluminum with high stacking fault energy. Amorphous powders were consolidated via spark plasma sintering at 300 and 500 °C by applying a constant pressure of 500 MPa. X-ray diffraction was performed on the 300- and 500 °C-sintered samples. XRD patterns of the 300 °C-sintered alloys exhibited very-low-intensity nanocrystalline FCC-Al peak overlaying an amorphous hump evincing retention of a large amount of the amorphous phase. Enhanced devitrification tendency was reported in the 500 °C-sintered alloys; however, a major difference in the devitrification tendency of the 500 °C-sintered Al86Ni8Y6, Al86Ni6Y6Co2 and Al86Ni6Y4.5Co2La1.5 alloys was that the quinary alloy exhibited higher tendency of devitrification, which was also corroborated by performing HRTEM and analytical TEM experiment. This could be attributed to the higher probability of coupling of atoms by short-range atomic shuffling during spark plasma sintering. Vickers hardness, and relative density estimated via Archimedes’ principle, varied depending on the degree of free volume annihilation and crystallization during sintering.

Sign in / Sign up

Export Citation Format

Share Document