scholarly journals Powder Metallurgy Processing and Mechanical Properties of Controlled Ti-24Nb-4Zr-8Sn Heterogeneous Microstructures

Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1626
Author(s):  
Benoît Fer ◽  
David Tingaud ◽  
Azziz Hocini ◽  
Yulin Hao ◽  
Eric Leroy ◽  
...  

This paper gives some insights into the fabrication process of a heterogeneous structured β-metastable type Ti-24Nb-4Zr-8Sn alloy, and the associated mechanical properties optimization of this biocompatible and low elastic modulus material. The powder metallurgy processing route includes both low energy mechanical ball milling (BM) of spherical and pre-alloyed powder particles and their densification by Spark Plasma Sintering (SPS). It results in a heterogeneous microstructure which is composed of a homogeneous 3D network of β coarse grain regions called “core” and α/β dual phase ultra-fine grain regions called “shell.” However, it is possible to significantly modify the microstructural features of the alloy—including α phase and shell volume fractions—by playing with the main fabrication parameters. A focus on the role of the ball milling time is first presented and discussed. Then, the mechanical behavior via shear tests performed on selected microstructures is described and discussed in relation to the microstructure and the probable underlying deformation mechanism(s).

2002 ◽  
Vol 740 ◽  
Author(s):  
Mats Carlsson ◽  
Mats Johnsson ◽  
Annika Pohl

ABSTRACTCeramic composites containing 2 and 5vol. % of nanosized commercially available TiN and SiC particles in alumina were prepared via a water based slurry processing route followed by spark plasma sintering (SPS) at 75 MPa in the temperature range 1200–1600°C. Some of the samples could be fully densified by use of SPS already after five minutes at 1200°C and 75 MPa. The aim was to control the alumina grain growth and thus obtain different nano-structure types. The microstructures have been correlated to some mechanical properties; e.g. hardness and fracture toughness.


2018 ◽  
Vol 784 ◽  
pp. 15-20 ◽  
Author(s):  
Petr Haušild ◽  
Jaroslav Čech ◽  
Miroslav Karlík ◽  
Filip Průša ◽  
Pavel Novák ◽  
...  

The effect of processing conditions on microstructure and mechanical properties of Fe-Al-Si powders was studied by means of scanning electron microscopy, X-ray diffraction and nanoindentation. Fe-Al-Si alloy powder was prepared from pure elemental powders by mechanical alloying. Microstructure and mechanical properties of powders were characterized after various durations of mechanical alloying. Special sample preparation technique was developed allowing to characterize the properties of individual powder particles after each step of processing in a planetary ball mill. This step-by-step characterization allowed to find the optimum conditions for subsequent spark plasma sintering.


2015 ◽  
Vol 782 ◽  
pp. 113-118
Author(s):  
Ying Mei Teng ◽  
Zhao Hui Zhang ◽  
Zi Zhou Yuan

The bulk nanocrystalline (NC) aluminum (Al) 5083 was synthesized by spark plasma sintering (SPS) technique with low initial pressure of 1 MPa, high holding pressure of 300 MPa and holding time of 4 min at different sintering temperatures, using surface passivated nanopowders. The effect of sintering temperature on microstructure and mechanical properties of the bulk NC Al 5083 were investigated. Results indicate that the density, grain size, the hardness and the compressive strength of the bulk NC Al 5083 increase with an increase in sintering temperature. The mechanical properties of the material are greatly improved due to the fine grain size. The bulk NC Al 5083 sintered at 723 K has the highest micro-hardness of 2.37 GPa and the best compressive strength of 845 MPa.


2017 ◽  
Vol 270 ◽  
pp. 197-204 ◽  
Author(s):  
Vojtěch Kučera ◽  
Filip Průša ◽  
Dalibor Vojtěch

Typically, conventional casting technologies are employed to manufacture aluminium alloys from scrap, but during recycling iron accumulates and increases in content. Increased iron content in such alloys reduces their mechanical properties. Because powder metallurgy is able to prepare materials with a very fine microstructure, we investigated its use for the preparation of aluminium alloys with a high iron content and the required mechanical properties. We prepared an Al-Fe17 (wt. %) binary alloy using combination of mechanical working (MW), high-energy ball milling (HEBM) and spark plasma sintering (SPS). The thus-prepared samples were analyzed (XRD, XRF, SEM-EDS, compression stress-strain test) and compared to the commercially-available alloy Al-Si12-Cu1-Mg1-Ni1, which is thermally stable. While the MW followed by SPS sample showed improved plastic deformation, the combination of MW, HEBM and SPS led to the absence of plastic deformation at room temperature. However, the MW+HEBM+SPS had much higher strength (579 MPa) and possessed similar thermal stability as the commercial Al-Si12-Cu1-Mg1-Ni1.


2012 ◽  
Vol 236-237 ◽  
pp. 113-117
Author(s):  
Song Wang ◽  
Ming Xie

W-26Re alloy was fabricated by spark plasma sintering (SPS) technology. The phases, microstructures and mechanical properties of the alloy were investigated by X-ray diffraction, optical light microscope, scanning electron microscope, energy dispersion spectroscope, digital display micro-hardness tester and tensile test. Results show that, using SPS technique can prepare W-26Re alloy with high density, fine grain and excellent mechanical properties. The relative density of W-26Re alloy was 96.2%. The main phases in the alloy were determined by the amount of (W) solid solution and the intermetallic  phases. The micro-hardness was 729HV, the ultimate tensile strength was 1680MPa, yield tensile strength was 1143MPa and elongation of alloy was 8.7%.


2009 ◽  
Vol 24 (6) ◽  
pp. 2118-2122 ◽  
Author(s):  
Y.Y. Li ◽  
C. Yang ◽  
W.P. Chen ◽  
X.Q. Li ◽  
S.G. Qu

We report on the formation of ultrafine-grained Ti66Nb13Cu8Ni6.8Al6.2 composites with in situ precipitated micrometer-sized β-Ti(Nb) phase by spark plasma sintering with crystallization. Microstructure analysis indicated that all alloys consisted of soft (Cu, Ni)Ti2 regions surrounded by hard β-Ti(Nb) regions but displayed different microstructures. The alloys exhibited high fracture strength of more than 2200 MPa and remarkable plasticity of ∼25%. The results provided a promising method for fabricating large-sized bulk composites with excellent mechanical properties by powder metallurgy.


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