Green Body Behaviour of High Velocity Pressed Metal Powder

High velocity compaction (HVC) is a production technique with capacity to significantly improve the mechanical properties of powder metallurgy (PM) parts. Several investigations indicate that high-density components can by obtained using HVC. Other characteristics are low ejection force and uniform density. Investigated here are green body data such as density, tensile strength, radial springback, ejection force and surface flatness. Comparisons are performed with conventional compaction using the same pressing conditions. Cylindrical samples of a pre-alloyed water atomized iron powder are used in this experimental investigation. The different behaviour of HVC-pressed green bodies compared to conventional pressed green bodies are analysed and discussed. The HVC process in this study resulted in a better compressibility curve and lower ejection force compared to conventional quasi static pressing. Vertical scanning interferometry (VSI) measurements show that the HVC process gives flatter sample surfaces.

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High Velocity Compaction of 316L Stainless Powder

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.44-47.2993 ◽

2010 ◽

Vol 44-47 ◽

pp. 2993-2997 ◽

Cited By ~ 1

Author(s):

Jin Chen ◽

Zhi Yu Xiao ◽

Chao Jie Li ◽

San Cai Deng ◽

Tung Wai Leo Ngai ◽

...

Keyword(s):

Impact Energy ◽

High Velocity ◽

Delay Time ◽

Green Density ◽

Single Impact ◽

Impact Process ◽

Ejection Force ◽

High Velocity Compaction ◽

Total Impact ◽

Double Impact

High velocity compaction technology was used to press 316L stainless powders. Effects of impact times on stress wave, green density and ejection force were analyzed. It was found that under the same total impact energy, the first loading time and the actuation duration of the second impact in double impact process were longer when compared with single impact process, while the first delay time was shorter. Furthermore, the green density of compacts prepared by double impact was greater than that prepared by single impact, but no obvious variation in maximum ejection force can be observed between single impact and double impact process.

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Effects of Sintering Temperature on Densification, Microstructure and Mechanical Properties of Al-Based Alloy by High-Velocity Compaction

Metals ◽

10.3390/met11020218 ◽

2021 ◽

Vol 11 (2) ◽

pp. 218

Author(s):

Xianjie Yuan ◽

Xuanhui Qu ◽

Haiqing Yin ◽

Zaiqiang Feng ◽

Mingqi Tang ◽

...

Keyword(s):

Mechanical Properties ◽

High Velocity ◽

Sintered Density ◽

Sintering Temperature ◽

X Ray Diffraction ◽

Scanning Calorimetry ◽

X Ray ◽

Transmission Electron ◽

High Velocity Compaction ◽

Sintered Temperature

This present work investigates the effects of sintering temperature on densification, mechanical properties and microstructure of Al-based alloy pressed by high-velocity compaction. The green samples were heated under the flow of high pure (99.99 wt%) N2. The heating rate was 4 °C/min before 315 °C. For reducing the residual stress, the samples were isothermally held for one h. Then, the specimens were respectively heated at the rate of 10 °C/min to the temperature between 540 °C and 700 °C, held for one h, and then furnace-cooled to the room temperature. Results indicate that when the sintered temperature was 640 °C, both the sintered density and mechanical properties was optimum. Differential Scanning Calorimetry, X-ray diffraction of sintered samples, Scanning Electron Microscopy, Energy Dispersive Spectroscopy, and Transmission Electron Microscope were used to analyse the microstructure and phases.

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High Velocity Compaction of Powder, 3rd Report

Journal of the Japan Society of Powder and Powder Metallurgy ◽

10.2497/jjspm.22.47 ◽

1975 ◽

Vol 22 (2) ◽

pp. 47-54

Author(s):

Yukio Sano ◽

Tadaaki Sugita

Keyword(s):

High Velocity ◽

High Velocity Compaction

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Determination of springback gradient in the die on compacted polymer powders during high-velocity compaction

Polymer Testing ◽

10.1016/j.polymertesting.2005.09.002 ◽

2006 ◽

Vol 25 (1) ◽

pp. 114-123 ◽

Cited By ~ 14

Author(s):

Bruska Azhdar ◽

Bengt Stenberg ◽

Leif Kari

Keyword(s):

High Velocity ◽

High Velocity Compaction ◽

Polymer Powders

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

Materials ◽

10.3390/ma12183005 ◽

2019 ◽

Vol 12 (18) ◽

pp. 3005 ◽

Cited By ~ 1

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.

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Quantitative investigation on force chain lengths during high velocity compaction of ferrous powder

Modern Physics Letters B ◽

10.1142/s0217984919501136 ◽

2019 ◽

Vol 33 (10) ◽

pp. 1950113 ◽

Cited By ~ 3

Author(s):

Wei Zhang ◽

Jian Zhou ◽

Xuejie Zhang ◽

Yan Zhang ◽

Kun Liu

Keyword(s):

High Velocity ◽

Pearson Correlation ◽

Quantitative Characteristic ◽

Correlation Coefficients ◽

High Strength ◽

Force Chain ◽

Force Chains ◽

Low Probability ◽

High Velocity Compaction ◽

Chain Lengths

Force chains play an important role in linking the macro- and micro-mechanisms of powder in high velocity compaction (HVC). Force chain lengths, as an important quantitative characteristic, can describe the geometry of force chains. In this study, force chain lengths and their relation to other force chain characteristics in HVC were investigated by discrete element method. Results revealed that force chain length decreased and it can be related to the densification process of ferrous powder in HVC. Moreover, long force chains extended from top to bottom and may play a major role in supporting load, although the percentage of long force chains was low. Probability density functions of force chain lengths further showed the exponential decay. The proportion of short force chains increased and the proportion of long force chains decreased. Long force chains had high strength and can be aligned to the direction of the external load, but force chain lengths did not have clear relation to straightness. These relations were confirmed by Pearson correlation coefficients.

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