Encyclopedie de la recherche sur l'aluminium au Quebec - Edition 2014 | Page 78

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TRANSFORMATION ET APPLICATIONS // TRANSFORMATION AND APPLICATIONS

ÉVALUATION DE L’EFFET DE GÉOMÉTRIES
ÉVALUATION DE L'EFFET DE GÉOMÉTRIES TRIANGULAIRESMOULES POUR LE
TRIANGULAIRES DES DES
MOULES POUR LE FRITTAGE PAR DÉCHARGE PLASMA D'Al 7075 PLASMA D’AL
FRITTAGE PAR DÉCHARGE
7075
EVALUATION OF TRIANGULAR DIE GEOMETRIES

EVALUATION OF TRIANGULAR DIE GEOMETRIES FOR

FOR SPARK PLASMA SINTERING OF AA7075 PLASMA SINTERING OF AA7075
SPARK
M.M.Tünçay1, M. Brochu1
1

Department of Mining and Materials Engineering, McGill University, Montreal, Quebec

INTRODUCTION

Spark Plasma Sintering (SPS) is a powder metallurgy (P/M) process, which uses pulsed high DC current simultaneously with uniaxial pressure to sinter
powders held in a graphite die. Geometry of the sample studied is usually cylindrical for SPS studies. However, increasing the size or complexity of the
samples shape could lead to thermal and pressure gradients resulting from the ”alteration” of the current flow, heat distribution and pressure. These
gradients can lead to an inhomogeneous densification affecting the mechanical properties of the final product.

RESULTS

OBJECTIVE

• To investigate the effect of the triangular geometry on the homogeneity
of the densification and on the mechanical properties of SPS samples of
aluminum alloy 7075 (AA 7075) in comparison with cylindrical samples.

Densification

- Full density
- Archimedean gives also
above 99.5 %

METHODOLOGY
Material:

 AA7075 micron size
atomized powder (20 µm)

Densification

Mechanical
Properties

SPS:






50 MPa
100 C/min heating rate
400 C peak Temp.
5 min. holding time
3 and 7 mm thick
samples

 Archimedean
 Optical mic.

 Microhardness
 Shear Punch
 Nano-impact

Nano-impact Test

mm

Microhardness

Mehmet Masum Tünçay
Mathieu Brochu
Département de génie des
mines et des matériaux,
Université McGill

Shear Punch Test
Shear Punch
Yield
Ø1.55mm
Strength
(MPa)
0.6 mm

Max.
Shear Punch
Strength
(MPa)

UTS  C max

a

UTS
(MPa)
C is 1.8 for
Al alloys*

Cylindrical center

90±8

125±12

225±21

Cylindrical edge

80±7

123±13

222±23

Triangular center

79±2

128±5

b

230±9

Triangular edge

87±6

136±6

244±15





Fracture surfaces:
a) Cylindrical sample
b) Triangular sample

CONCLUSION

Fully dense samples both for triangular and cylindrical shapes with 3 mm
and 7 mm thickness
Mechanical properties are within the same range regardless of the
shape and thickness
Fracture surfaces show incomplete bonding between the particles
regardless of the shape

*R. K. Guduru, K. A. Darling, R. Kishore, R. O. Scattergood, C. C. Koch, and K. L. Murty, “Evaluation of mechanical properties
using shear–punch testing,” Materials Science and Engineering: A, vol. 395, no. 1–2, pp. 307-314, 2005

Journée des étudiants – REGAL
Spark Plasma Sintering (SPS) is a powder metallurgy (P/M) process, which uses

Le frittage par décharge plasma (FDP) est un procédé de métallurgie des poudres
qui utilise des impulsions intenses de courant continu simultanément avec
l’application d’une pression uniaxiale dans le but de fritter la poudre contenue
dans un moule de graphite. Comparativement aux procédés conventionnels de
métallurgie des poudres, le FDP offre des vitesses de frittage significativement
plus élevées ainsi que des durées d’opération plus courtes par