scholarly journals Bimodal Microstructure in an AlZrTi Alloy Prepared by Mechanical Milling and Spark Plasma Sintering

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3756
Author(s):  
Orsolya Molnárová ◽  
Jan Duchoň ◽  
Esther de Prado ◽  
Štefan Csáki ◽  
Filip Průša ◽  
...  
Keyword(s):  
Spark Plasma Sintering ◽  
Mechanical Milling ◽  
Milled Powder ◽  
Sintered Sample ◽  
Second Phase ◽  
Bimodal Microstructure ◽  
Plasma Sintering ◽  
Second Phase Particles ◽  
Spark Plasma ◽  
Powder Particles

The aim of this study was to prepare a low porosity bulk sample with a fine-grained structure from an AlZrTi alloy. Nanostructured powder particles were prepared by mechanical milling of gas atomized powder. The mechanically milled powder was consolidated using spark plasma sintering technology at 475 °C for 6 min using a pressure of 100 MPa. Sintering led to a low porosity sintered sample with a bimodal microstructure. The sintered sample was revealed to be composed of non-recrystallized grains with an approximate size of about 100 nm encompassed by distinct clusters of coarser, micrometer-sized grains. Whereas the larger grains were found to be lean on second phase particles, a high density of second phase particles was found in the areas of fine grains. The microhardness of the milled powder particles was established to be 163 ± 15 HV0.01, which decreased to a slightly lower value of 137 ± 25 HV0.01 after sintering.

scholarly journals Mechanical Properties of Ti-15Mo Alloy Prepared by Cryogenic Milling and Spark Plasma Sintering

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1280 ◽  
Author(s):  
Anna Veverková ◽  
Jiří Kozlík ◽  
Kristína Bartha ◽  
Tomáš Chráska ◽  
Cinthia Antunes Corrêa ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Spark Plasma Sintering ◽  
Milled Powder ◽  
Two Phase ◽  
High Oxygen Content ◽  
Cryogenic Milling ◽  
Plasma Sintering ◽  
Refined Microstructure ◽  
Spark Plasma ◽  
Powder Particles

Metastable β-Ti alloy Ti-15Mo was prepared by cryogenic ball milling in a slurry of liquid argon. Material remained ductile even at low temperatures, which suppressed particle refinement, but promoted intensive plastic deformation of individual powder particles. Repetitive deformation of powder particles is similar to the multidirectional rolling and resembles bulk severe plastic deformation (SPD) methods. Initial and milled powders were compacted by spark plasma sintering. Sintered milled powder exhibited a refined microstructure with small β-grains and submicrometer sized α-phase precipitates. The microhardness and the yield tensile strength of the milled powder after sintering at 850 °C attained 350 HV and 1200 MPa, respectively. Low ductility of the material can be attributed to high oxygen content originating from the cryogenic milling. This pioneering work shows that cryogenic milling followed by spark plasma sintering is able to produce two-phase β-Ti alloys with refined microstructure and very high strength levels.

scholarly journals Microstructure and texture in cryomilled and spark plasma sintered Ti Grade 2

2020 ◽  
Vol 321 ◽  
pp. 12030
Author(s):  
Jiří Kozlík ◽  
Josef Stráský ◽  
Petr Harcuba ◽  
Tomáš Chráska ◽  
Miloš Janeček
Keyword(s):  
Grain Size ◽  
Spark Plasma Sintering ◽  
Milled Powder ◽  
Recrystallization Process ◽  
Advanced Technique ◽  
Microstructural Investigation ◽  
Cryogenic Milling ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Powder Particles

Titanium (Grade 2) was processed by cryogenic milling and subsequently sintered by spark plasma sintering (SPS) method with the aim of creating and preserving the ultra-fine grained (UFG, < 1 μm) microstructure. Microstructural investigation was performed after both cryogenic milling and spark plasma sintering. An advanced technique of transmission Kikuchi diffraction (TKD) was used to characterize the individual milled powder particles. Investigations of milled powders showed significant grain refinement down to 50 nm after milling in liquid argon with tungsten carbide balls. We assume that this is the equilibrium grain size resulting from the balance of deformation, recovery and dynamic recrystallization. A texture, resembling the rolling texture in Ti, was also found in the milled particles, which can be explained by the nature of deformation during milling. UFG microstructure was not maintained after sintering, with the mean grain size of 2.6 μm. Although the grains are completely recrystallized, a texture, similar to the powder texture, was also found in these samples as a result of packing of the powder particles and the nature of the recrystallization process (continuous static recrystallization).

scholarly journals Effect of Nano-Y2O3 Addition on Microstructure and Tensile Properties of High-Nb TiAl Alloy Prepared by Spark Plasma Sintering

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1048
Author(s):  
Yingchao Guo ◽  
Yongfeng Liang ◽  
Junpin Lin ◽  
Fei Yang
Keyword(s):  
Tensile Strength ◽  
Spark Plasma Sintering ◽  
Tial Alloy ◽  
Second Phase ◽  
Fine Grain ◽  
Fine Grain Strengthening ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Y2o3 Addition ◽  
Powder Metallurgy Route

Nano-Y2O3 reinforced Ti-47.7Al-7.1Nb-(V, Cr) alloy was fabricated by a powder metallurgy route using spark plasma sintering (SPS), and the influence of nano-Y2O3 contents on the microstructure and mechanical properties were investigated systematically. The results revealed that the ultimate tensile strength and elongation of the alloy were 570 ± 28 MPa and 1.7 ± 0.6% at 800 °C, 460 ± 23 MPa and 6.1 ± 0.4% at 900 °C with no nano-Y2O3, 662 ± 24 MPa and 5.5 ± 0.5% at 800 °C, and 466 ± 25 MPa and 16.5 ± 0.8% at 900 °C with 0.05 at% nano-Y2O3 addition, respectively. Due to the fine-grain strengthening and the second-phase strengthening, both tensile strength and elongation of the high-Nb TiAl alloy were enhanced with the addition of nano-Y2O3.

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

Microstructure and properties of Cu-10 wt.% Al bronze obtained by high-energy mechanical milling and spark plasma sintering

2022 ◽  
pp. 131671
Author(s):  
Dina V. Dudina ◽  
Tatyana F. Grigoreva ◽  
Vyacheslav I. Kvashnin ◽  
Evgeniya T. Devyatkina ◽  
Sergey V. Vosmerikov ◽  
...  
Keyword(s):  
Spark Plasma Sintering ◽  
Mechanical Milling ◽  
High Energy ◽  
Microstructure And Properties ◽  
Plasma Sintering ◽  
Spark Plasma

scholarly journals Mechanical Milling-Assisted Spark Plasma Sintering of Fine-Grained W-Ni-Mn Alloy

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1323 ◽  
Author(s):  
Yanlin Pan ◽  
Daoping Xiang ◽  
Ning Wang ◽  
Hui Li ◽  
Zhishuai Fan
Keyword(s):  
Spark Plasma Sintering ◽  
Mechanical Milling ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Interface Fracture ◽  
Composite Powders ◽  
Fine Grained ◽  
Plasma Sintering ◽  
Binding Phase ◽  
Spark Plasma

Fine-grained W-6Ni-4Mn alloys were fabricated by spark plasma sintering (SPS) using mechanical milling W, Ni and Mn composite powders. The relative density of W-6Ni-4Mn alloy increases from 71.56% to 99.60% when it is sintered at a low temperature range of 1000–1200 °C for 3 min. The spark plasma sintering process of the alloy can be divided into three stages, which clarify the densification process of powder compacts. As the sintering temperature increases, the average W grain size increases but remains at less than 7 µm and the distribution of the binding phase is uniform. Transmission electron microscopy (TEM) observation reveals that the W-6Ni-4Mn alloy consists of the tungsten phase and the γ-(Ni, Mn, W) binding phase. As the sintering temperature increases, the Rockwell hardness and bending strength of alloys initially increases and then decreases. The optimum comprehensive hardness and bending strength of the alloy are obtained at 1150 °C. The main fracture mode of the alloys is W/W interface fracture.

Nonstoichiometric Composition and Densification of CaRuO3 by SPS

2007 ◽  
Vol 352 ◽  
pp. 251-254 ◽  
Author(s):  
Nittaya Keawprak ◽  
Rong Tu ◽  
Takashi Goto
Keyword(s):  
Spark Plasma Sintering ◽  
Single Phase ◽  
Lattice Parameters ◽  
Second Phase ◽  
Nonstoichiometric Composition ◽  
Plasma Sintering ◽  
Spark Plasma

Calcium ruthenates were prepared in different ratios of Ru to Ca (RRu/Ca = 0.5～1.4) by spark plasma sintering. CaRuO3 in a single phase was obtained at RRu/Ca = 1.0. At RRu/Ca < 1.0, a mixture of CaRuO3 and CaO was obtained, whereas CaRuO3 with second phase of RuO2 was obtained at RRu/Ca > 1.0. The density at RRu/Ca < 1.0 were 80-85% and slightly increased with increasing RRu/Ca. The density significantly increased up to 95% with increasing RRu/Ca from 1.1 to 1.4, suggesting that the second phase of RuO2 was effective to densify CaRuO3. The density of CaRuO3 in a single phase was 82% at most. The lattice parameters of CaRuO3 decreased with increasing RRu/Ca from 0.7 to 1.0, showing a nonstoichiometric range of Ca1+δRuO3+δ.

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