Study of the Dynamics of the Agglomerate Layer Thickness Under Mechanical Activation of a Ti + Ni Powder Mixture

The mechanical activation of the Ni85.8Fe10.6Cu2.2W1.4 powder mixture in the time intervals of 30-210 min in combination with thermal treatment at 393-873 K resulted in microstructural changes, forming the nanostructured mixture of the same composition but improved magnetic properties. The best result were achieved for mechanical activation during 120 min and thermal treatment at temperatures close to the Curie temperature (693K), enhancing the mass magnetization of the starting powder mixture by about 57%. The microstructural changes, which include the structural relaxation, decrease in free volume, density of dislocation and microstrain, improve structural characteristics of material, enabling better mobility of walls of magnetic domains and their better orientation in applied magnetic field and consequently enabling better mass magnetization of the material. With longer time of milling, the growing stress introduced in the sample undergoes easier relief, relocating stress-relieving processes toward lower temperatures.

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The possibility to control the thickness of the oxide layer on the titanium Grade 2 by mechanical activation and heat treatment

Journal of Achievements of Materials and Manufacturing Engineering ◽

10.5604/01.3001.0014.3346 ◽

2020 ◽

Vol 2 (100) ◽

pp. 70-77

Author(s):

M. Szota ◽

A. Łukaszewicz ◽

K. Machnik

Keyword(s):

Heat Treatment ◽

Mechanical Activation ◽

Oxide Layer ◽

Layer Thickness ◽

Pure Titanium ◽

Medical Application ◽

Oxide Layer Thickness ◽

Surface Development ◽

Titanium Grade ◽

Practical Implications

Purpose: The paper presents the results of microstructure, surface development and thickness of the oxide layer on the pure titanium Grade 2 after mechanical activation and heat treatment (550°C/5h). Design/methodology/approach: Studies show that it is possible to control the thickness of the oxide layer by using different materials to change the roughness of surface - mechanical activation before heat treatment. After mechanical activation and heat treatment, the results of the thickness of the oxide layer as well as a level of surface development were obtained, presented and discussed. Findings: The conducted research have proved that mechanical activation of the surface which cause increase of surface development results in greater thickness of oxide layer which is formed during heat treatment. Nevertheless mechanical activation that results in decrease of surface development, such as polishing, results in decrease of oxide layer thickness. Research limitations/implications: The conducted research have showed up that mechanical activation of the surface which cause increase of surface development results in greater thickness of oxide layer which is formed during heat treatment. Nevertheless, mechanical activation that results in decrease of surface development, such as polishing, results in decrease of oxide layer thickness. Practical implications: are possible using similar method for passivation titanium alloys for medical application. Originality/value: The paper presents the possibility of using mechanical preactivation of surface before heat treatment passivation.

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Synthesis of Intermetallic Compound in Isochronal Heating of Al/Ni Powder Mixture and its Forming.

Journal of the Japan Society of Powder and Powder Metallurgy ◽

10.2497/jjspm.49.52 ◽

2002 ◽

Vol 49 (1) ◽

pp. 52-57

Author(s):

Eiji Yuasa ◽

Kosuke Yamaguchi ◽

Katsuyoshi Kondou ◽

Tatsuhiko Aizawa

Keyword(s):

Intermetallic Compound ◽

Powder Mixture ◽

Ni Powder

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Self-Combustion Reactions Induced by Mechanical Activation: Formation of Aluminum Nitride from Aluminum-Graphite Powder Mixture

Journal of the American Ceramic Society ◽

10.1111/j.1151-2916.1994.tb04574.x ◽

1994 ◽

Vol 77 (12) ◽

pp. 3227-3231 ◽

Cited By ~ 32

Author(s):

Takeshi Tsuchida ◽

Takeshi Hasegawa ◽

Michio Inagaki

Keyword(s):

Aluminum Nitride ◽

Mechanical Activation ◽

Powder Mixture ◽

Graphite Powder

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Ti-Ni Powder Structure after Mechanical Activation and Interaction with Hydrogen

Russian Physics Journal ◽

10.1007/s11182-019-01873-y ◽

2019 ◽

Vol 62 (8) ◽

pp. 1455-1460 ◽

Cited By ~ 1

Author(s):

E. V. Abdul’menova ◽

S. N. Kul’kov

Keyword(s):

Mechanical Activation ◽

Ni Powder

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Synchrotron in situ studies of mechanical activation treatment and γ-radiation impact on structural-phase transitions and high-temperature synthesis parameters during the formation of γ-(TiAl) compound

Journal of Synchrotron Radiation ◽

10.1107/s1600577519010014 ◽

2019 ◽

Vol 26 (5) ◽

pp. 1671-1678 ◽

Cited By ~ 1

Author(s):

Marina Loginova ◽

Alexey Sobachkin ◽

Alexander Sitnikov ◽

Vladimir Yakovlev ◽

Valeriy Filimonov ◽

...

Keyword(s):

High Temperature ◽

Mechanical Activation ◽

Thermal Explosion ◽

Powder Mixture ◽

Maximum Temperature ◽

Γ Irradiation ◽

Temperature Synthesis ◽

High Temperature Synthesis ◽

The Impact

In situ synchrotron studies of structure and phase formation dynamics in mechanically activated (t = 7 min, power density 40 g) and mechanically activated with subsequent irradiation by γ-quanta 60Co powder mixture (Ti 64 wt% + Al) during high-temperature synthesis by the method of thermal explosion using induction heating are described. In situ high-temperature synthesis was carried out on the created experimental complex adapted for synchrotron X-ray diffraction methods. The sequence of formation and time–temperature interval of the metastable and main phases were determined. The impact of preliminary mechanical activation and of γ-irradiation on the macrokinetic parameters of the synthesis were studied experimentally in situ. It has been established that the impact of γ-irradiation on the mechanically activated powder mixture of the composition Ti 64 wt% + Al leads to a change in the thermal parameters of combustion: the maximum synthesis temperature and the burning rate decrease. The heating rate for the non-irradiated mixture is 204.8 K s−1 and that for the irradiated mixture is 81.6 K s−1. The dependences of mass fractions of the synthesized compounds on time and temperature were calculated from the stage of preheating until completion of the thermal explosion. A single-phase equilibrium product of the composition γ-(TiAl) is formed in γ-irradiated mechanically activated mixture when the system reaches maximum temperature. The synthesized product of the mechanically activated mixture without γ-irradiation contains 72% γ-(TiAl); TiAl3 (26%) and residual Ti (2%) are also observed.

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