Shock consolidation of Ni-Ti alloy powder

1986 ◽  
Vol 44 ◽  
pp. 430-431
Author(s):  
Naresh N. Thadhani ◽  
Thad Vreeland ◽  
Thomas J. Ahrens
Keyword(s):  
Alloy Powder ◽  
Amorphous Material ◽  
Ti Alloy ◽  
Two Phase ◽  
Near Surface ◽  
Optical Micrograph ◽  
Shock Compaction ◽  
Powder Particles ◽  
Ti Powder ◽  
Rapidly Solidified

A spherically-shaped, microcrystalline Ni-Ti alloy powder having fairly nonhomogeneous particle size distribution and chemical composition was consolidated with shock input energy of 316 kJ/kg. In the process of consolidation, shock energy is preferentially input at particle surfaces, resulting in melting of near-surface material and interparticle welding. The Ni-Ti powder particles were 2-60 μm in diameter (Fig. 1). About 30-40% of the powder particles were Ni-65wt% and balance were Ni-45wt%Ti (estimated by EMPA).Upon shock compaction, the two phase Ni-Ti powder particles were bonded together by the interparticle melt which rapidly solidified, usually to amorphous material. Fig. 2 is an optical micrograph (in plane of shock) of the consolidated Ni-Ti alloy powder, showing the particles with different etching contrast.

scholarly journals Effects of Compaction Velocity on the Sinterability of Al-Fe-Cr-Ti PM Alloy

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 3005 ◽  
Author(s):  
Xianjie Yuan ◽  
Xuanhui Qu ◽  
Haiqing Yin ◽  
Zhenwei Yan ◽  
Zhaojun Tan
Keyword(s):  
Mechanical Properties ◽  
High Velocity ◽  
Alloy Powder ◽  
Sintered Density ◽  
Ti Alloy ◽  
Maximum Elongation ◽  
Nitrogen Gas ◽  
High Velocity Compaction ◽  
Ti Powder ◽  
Particle Boundary

In this research, the effects of the compaction velocity on the sinterability of the Al–Fe–Cr–Ti powder metallurgy (PM) alloy by high velocity compaction were investigated. The Al–Fe–Cr–Ti alloy powder was compacted with different velocities by high velocity compaction and then sintered under a flow of high pure (99.999 wt%) nitrogen gas. Results indicated that both the sintered density and mechanical properties increased with increasing compaction velocity. By increasing the compaction velocity, the shrinkage of the sintered samples decreased. A maximum sintered density of 2.85 gcm−3 (relative density is 98%) was obtained when the compaction velocity was 9.4 ms−1. The radial and axial shrinkage were controlled to less than 1% at a compaction velocity of 9.4 ms−1. At a compaction velocity of 9.4 ms−1, sintered compacts with an ultimate tensile strength of 222 MPa and a yield strength of 160 MPa were achieved. The maximum elongation was observed to be 2.6%. The enhanced tensile properties of the Al–Fe–Cr–Ti alloy were mainly due to particle boundary strengthening.

Precipitation and Recovery Near Interparticle Regions In Explosively Consolidated 304 Stainless Steel Rapidly Solidified Powders

1985 ◽  
Vol 43 ◽  
pp. 40-41
Author(s):  
L. H. Schoenlein ◽  
G. E. Korth ◽  
J. E. Flinn
Keyword(s):  
Stainless Steel ◽  
Temperature Rise ◽  
304 Stainless Steel ◽  
Structural Defects ◽  
Bulk Temperature ◽  
Gas Atomization ◽  
Dissolved Gas ◽  
Near Surface ◽  
Powder Particles ◽  
Rapidly Solidified

Rapid solidification often produces new and unique alloy microstructures. Retention of these microstructures may be accomplished by dynamic consolidation, the bulk temperature rise generated by this technique is quite low. However, at near-surface regions of powder particles the temperature rise can be substantial and may cause extensive recovery, recrystallization or remelting of these areas.Examination of explosively-consolidated 304 stainless steel powders produced by dissolved gas atomization was performed by TEM. Particle interiors contained copious dislocations, twins and stacking faults, typical of shock-hardened materials. Some interparticle regions (Figure 1) contained few structural defects, apart from a network of low angle boundaries, indicating that extensive recovery occurred. The extent of these areas is typically ∼5 μm and the average subgrain is ∼0.5 μm in diameter. Precipitation also occurred in these areas, as discussed below, but was not observed in the particle interiors.

On the Origin of the Microscystalline Structure in Rapidly Solidified IN-100 Powder

1977 ◽  
Vol 35 ◽  
pp. 260-261
Author(s):  
J. M. Walsh ◽  
K. P. Gumz ◽  
J. C. Whittles ◽  
B. H. Kear
Keyword(s):  
The Other ◽  
Coarse Grained ◽  
Microcrystalline Structure ◽  
Routine Examination ◽  
Atomization Process ◽  
Centrifugal Atomization ◽  
Splat Quenching ◽  
Powder Particles ◽  
Dendritic Microstructures ◽  
Rapidly Solidified

During a routine examination of the microstructure of rapidly solidified IN-100 powder, produced by a newly-developed centrifugal atomization process1, essentially two distinct types of microstructure were identified. When a high melt superheat is maintained during atomization, the powder particles are predominantly coarse-grained, equiaxed or columnar, with distinctly dendritic microstructures, Figs, la and 4a. On the other hand, when the melt superheat is reduced by increasing the heat flow to the disc of the rotary atomizer, the powder particles are predominantly microcrystalline in character, with typically one dendrite per grain, Figs, lb and 4b. In what follows, evidence is presented that strongly supports the view that the unusual microcrystalline structure has its origin in dendrite erosion occurring in a 'mushy zone' of dynamic solidification on the disc of the rotary atomizer.The critical observations were made on atomized material that had undergone 'splat-quenching' on previously solidified, chilled substrate particles.

Development of Biodegradable Mg-Ti Alloy Synthesized Using Mechanical Alloying

2016 ◽  
Vol 1133 ◽  
pp. 75-79 ◽  
Author(s):  
Emee Marina Salleh ◽  
Sivakumar Ramakrishnan ◽  
Zuhailawati Hussain
Keyword(s):  
Mechanical Alloying ◽  
Milling Time ◽  
Milled Powder ◽  
Milling Process ◽  
Planetary Mill ◽  
Ti Alloy ◽  
X Ray Diffraction ◽  
Argon Flow ◽  
Diffraction Patterns ◽  
Ti Powder

The aim of this work was to study the effect of milling time on binary magnesium-titanium (Mg-Ti) alloy synthesized by mechanical alloying. A powder mixture of Mg and Ti with the composition of Mg-15wt%Ti was milled in a planetary mill under argon atmosphere using a stainless steel container and balls. Milling process was carried out at 400 rpm for various milling time of 2, 5, 10, 15 and 30 hours. 3% n-heptane solution was added prior to milling process to avoid excessive cold welding of the powder. Then, as-milled powder was compacted under 400 MPa and sintered in a tube furnace at 500 °C in argon flow. The refinement analysis of the x-ray diffraction patterns shows the presence of Mg-Ti solid solution when Mg-Ti powder was mechanically milled for 15 hours and further. Enhancements of Mg-Ti phase formation with a reduction in Mg crystallite size were observed with the increase in milling time. A prolonged milling time has increased the density and hardness of the sintered Mg-Ti alloy.

Effect of Composition on the Morphology and Hardness of Nanostructured Cu Based Composite and Alloy Powders/Granules Produced by High Energy Mechanical Milling

2007 ◽  
Vol 29-30 ◽  
pp. 143-146 ◽  
Author(s):  
Aamir Mukhtar ◽  
De Liang Zhang ◽  
C. Kong ◽  
P. R. Munroe
Keyword(s):  
Grain Size ◽  
Mechanical Milling ◽  
Alloy Powder ◽  
High Energy ◽  
Al2o3 Nanoparticles ◽  
X Ray ◽  
Fine Powders ◽  
Average Grain Size ◽  
Powder Particles

Cu-(2.5 or 5.0vol.%)Al2O3 nanocomposite balls and granules and Cu-(2.5vol.% or 5.0vol.%)Pb alloy powder were prepared by high energy mechanical milling (HEMM) of mixtures of Cu and either Al2O3 or Pb powders. It was observed that with the increase of the content of Al2O3 nanoparticles from 2.5vol.% to 5vol.% in the powder mixture, the product of HEMM changed from hollow balls into granules and the average grain size and microhardness changed from approximately 130nm and 185HV to 100nm and 224HV, respectively. On the other hand, HEMM of Cu–(2.5 or 5.0vol.%) Pb powder mixtures under the same milling conditions failed to consolidate the powder in-situ. Instead, it led to formation of nanostructured fine powders with an average grain size of less than 50nm. Energy dispersive X-ray mapping showed homogenous distribution of Pb in the powder particles in Cu–5vol.%Pb alloy powder produced after 12 hours of milling. With the increase of the Pb content from 2.5 to 5.0 vol.%, the average microhardness of the Cu-Pb alloy powder particles increases from 270 to 285 HV. The mechanisms of the effects are briefly discussed.

Study on synthesis of Zr–Ti alloy powder using molten magnesium

2013 ◽  
Vol 17 (sup2) ◽  
pp. s113-s117 ◽  
Author(s):  
D.-W. Lee ◽  
Y.-K. Baek ◽  
W.-J. Lee ◽  
J.-P. Wang
Keyword(s):  
Alloy Powder ◽  
Ti Alloy ◽  
Molten Magnesium

Advanced gas atomization processing for Ti and Ti alloy powder manufacturing

JOM ◽  
2010 ◽  
Vol 62 (5) ◽  
pp. 35-41 ◽  
Author(s):  
A. J. Heidloff ◽  
J. R. Rieken ◽  
I. E. Anderson ◽  
D. Byrd ◽  
J. Sears ◽  
...  
Keyword(s):  
Alloy Powder ◽  
Gas Atomization ◽  
Ti Alloy ◽  
Powder Manufacturing

scholarly journals Review of the Methods for Production of Spherical Ti and Ti Alloy Powder

JOM ◽  
2017 ◽  
Vol 69 (10) ◽  
pp. 1853-1860 ◽  
Author(s):  
Pei Sun ◽  
Zhigang Zak Fang ◽  
Ying Zhang ◽  
Yang Xia
Keyword(s):  
Alloy Powder ◽  
Ti Alloy

scholarly journals RGB color evolution: a digital tool for monitoring the visual changes of iron oxide pigments irradiated by infrared laser pulses

2011 ◽  
Vol 64 (2) ◽  
pp. 187-191
Author(s):  
Adilson Rodrigues da Costa ◽  
Flávio Sandro Lays Cassino ◽  
Rémy Chapoulie ◽  
Florence Rud
Keyword(s):  
Near Infrared ◽  
Amorphous Material ◽  
Laser Pulses ◽  
Color Measurement ◽  
Digital Tool ◽  
Color Changes ◽  
Color Evolution ◽  
Powder Particles ◽  
Iron Oxide Pigments ◽  
Fast Chemical

Laser irradiation of powdered iron oxides (goethite and hematite) was performed in order to obtain information about their interaction with short duration near-infrared pulses. Results have shown that under some conditions, Nd:YAG laser provides enough energy to induce fast chemical and structural transformations of the goethite and hematite. This kind of information is of great interest for professionals working with artwork conservation because this technique is used in the conservation of cultural heritage. Depending on the laser's working conditions, glassy (amorphous) material was detected and its presence was related to areas of fast solidification where the energy delivered was enough to melt the powder particles. Color changes were observed and quantified by means of an RGB color measurement method developed to show the evolution of each color component.

Sign in / Sign up

Export Citation Format

Share Document