Hot Explosive Pressingof High Strength and Superhard Materials

by

R. Prümmer, Germanyand

K. Hokamoto, Japan

EPNM-2008May 5-9, 2008. Lisse

Why Hot Expl. Pressing?HIP

Hot Isost.PressCEP

Cold Expl.PressHEP

Hot Expl. Press.

Pressure limited unlimited unlimited

Duration long shortseveral microsec.

shortseveral microsec.

Diffusion high limited high

Plasticdeformation low medium high

Melting,leadingto welding no locally very high

3

4

HEPUdimet 700

Ni-base Superalloy

5Composition of several Nickel based Superalloys

6Atomization of Udimet 700 - Powder

7

8 Density of Sample after HEP of Udimet 700- Powder

9Hardness of Samples vs. Temperature of HEP

1010

Micrograph of Sample showing surface melting

1113Strength of Sample vs. Temperature of HEP

12

HEPDiamond Powder, 4-8 um grain size

13Principle of Set-up for HEP

14

Set-up for HEP

15

Sample Set -up

High pressure due to mach stem and end plug

16

Sample, longitudinally cut open

17

Micrograph of polished Surface of Diamond Compact

18

Scanning Electron Micrograph of Fracture Surface

19X-ray Diffraction Pattern of Diamond Powder and Compactas delivered: black, after heat treatment: blue; compacted: red

As-received

1100 　 C

Compact

o

20

0 2 4 6 8

10

8

6

4

2 (a)　As-received(b)　1100oC

(c)　Compact　

cos

/.10

7(m

-1)

sin/.1010 (m-1)

0 2 4 6 8

10

8

6

4

2 (a)　As-received(b)　1100oC

(c)　Compact　

cos

/.10

7(m

-1)

sin/.1010 (m-1)

Hall-Williamson Plot of Diamond Powder and Compact

sin(/) ･ 1010 (m-1)

si

n(/

) ･1

07 (m

-1)

Slope;Lattice strain

ConclusionsThe effects of the use of hot explosive pressing are demonstrated at the present investigation for Udimet 700 and diamond powders.Surface melting and softening the powders improves the condition of compaction, and the compacts recovered show improved mechanical properties and the crystalline lattice strain.

21