Sliding wear of cemented carbides

nitriding

and sintering.

composite

Wear properties

were shown

to be superior

posites made from premixed anodised

Al alloys. The

under oil lubrication

of the to com-

powders and hard-

coefficient

Characterisation of hardmetals by a scanning depth hardness test

of friction B.Roehuck Teddington,

was said to be exception-

et

al.

non-standard

It was noted limited that

that

PM use of Ti was more

development

was likely to change atomisation

UK.)

metals

of new this. These

techniques

and

technologies included

new

for high quality

pow-

ders and mechanical

alloying

at low levels

contamination.

powders

can be consoli-

dated

The

by conventional

means

extrusion

and injection

methods

including

direct

laser

moulding

and

as HIP,

or by new

hardness,

was described.

variation

test machine,

using depthThe

was were

WC-

coated

material

to evaluate

device

to map

hardness

WC Data

hardness

maps

carried

out on a

the ability variations

into

shapes.

in

progress

work

These were

reviewed.

of the through

Three-dimensional

bimodal

WC-Co

tribution

in

scanning

electron

sections

and

algorithm.

were nitrided

by PM

Samples

cut from

in two stages

to 1500°C.

The second

in the

stage was

to allow TiN precipitates

to grow. Ductile/brit-

tle transitions

-200°C

between

temperature,

microstructure

and ambient

and bend strength

were investigated.

It was shown that the nitrid-

ing was effective

in improving

embrittlement

characteristics.

was

It was noted 0.3%La201

analysed

Measured

population

tions

considered.

to

a

bimodal

by

automatic fitted

prisms

and bimodal The

range

of

character

by

materials

an was

of trigonal

Unimodal

were

investigated

data

to

a

of condistribu-

method

WC-Co of the

the

size dis-

of

Keutte,ALcstria.)

C.Stallybrass et al. (Plansee AC,

grain

microscopy

stant shape.

The

were prepared

and rolled to sheet.

Effects of atmosphere dew point ‘on sintering doped molybdenum

A.Lackner et nl. (Plansee Tizit AG, Reutte, ALcstria.)

applied

University, Okayama, Japan.)

alloys

into the substrate.

Analysis of bimodal grain size distribution in tungsten carbide-cobalt

model

methods

range 800°C

described.

with

Tests

Mo-0.5wt%Ti the sheet

machine

with unconventional

uniformity

obtained.

the coating

auto-

A study of conventional

size distribution

concerning

of a new

Mechanical properties of nitrided molybdenum-titanium alloys M.Nagae et al. (Okayama

in mechani-

was reported.

Co and a material

were

have

that need char-

computer-controlled

deposition

techniques

such

of

high-speed

sensing

Laboratory,

hardmetals

Development

mated

grain

newer

for spatial

cal properties.

than for other non-ferrous

the

that

Physical

microstructures

acterisation

Recent developments in PM of titanium (DERA Farnboro~~h,Hampshire,

(Natwnal

UK.) It was noted

ally low.

P.S.Goodwin.

High-performance PM materials

was

grades.

distribution

that

during

atmosphere

entrapped

increased.

in the core

ing a dew point

gradient.

atmosphere

and structural increased

that the

densification.

of dew point

were

described. dew

temperature

dry H was higher

is creat-

on densification

increased

Density

of

Moisture

Effects

evolution

shown

moist

of MO-

of the samples,

of the sintering was

sintering

in H the water vapour content

onset

of

of samples

sintered

in

in samples

sintered

in

than

for

It

point

H.

was discussed.

Sliding wear of cemented carbides

Hard materials Novel plasticiser for extrusion cemented carbides J.C.Zhou, B.Y.Hwng. (Central Technology, Changsha, China.) It was reported extrusion

that

processing

materials

had been

of

structures

up to 25mm cessing

Wear

plasticiser

cemented

developed

for

and that use of

and good properties Properties

including

of

carbide

of materials

in diameter.

stages,

B.LJhreniu, et al. (AB Sandvik Hardmaterink, Stockholm, Sweden.)

of

South University

a novel

this had led to production uniform

thermal

with in rods

and pro-

tigated. Parameters of Cr3CZ,

Tic

increased

in various materials

MPR

Austria.) media

and

was inves-

and effects of additions

and TaC. by

the

Corrosion refractory

in abrasion

tests

inversely

dependent

on

considered

wear

October

rate

hardness.

difficult

to

Sliding

wear

predict

Fragmenting

from was

wear

phenomenon

mechanisms wear

being

Sliding

to be a surface

resistance carbide

2002

P.Polcik etal. (Plansee AG, Creep

50MPa,

1100°C

lower than

and

exponent

bulk

properties.

were

elucidated.

for

be

and

10

often

to

encountered,

A Norton-type were calculated

self-diffusion

mechanism

effective

that cemented

produced ment.

The

without

is shown

toughness

1.5 times greater

cemented

carbide

resistance.

Large

and

equip-

to have fracture

shown

to

could

main

dislocation

of the alloy elements were compared

for

Sintering of an MoFeB cermet and its composite with SIC fibres D.Rao, G..S.LJpadhyaya. Kanpur, India.) A MozFeBz_ composite

based

containing sintering

Vacuum

sintered

be made

Material

with Sic

of the need for high pressure

The be

creep reduction.

by two

higher

Activation

and were lower than

Effects

wear

than conventional

lo-times

components

mate-

had been

use of high-pressure

material

due to avoidance

carbide

particles

much

for up to 500

mechanisms.

was

900°C

creep law, with a stress

used, B, K, Re amd LazOj,

rials with dispersed diamond

both

of 1.0, was identified.

rearrangements.

cemented

of W and W

to

hours.

to

stability

in the ranges

energies

considered

Reutte, Au&a.)

and structural

alloys were investigated

was

important.

in manufacture.

additions.

46

measured

It was reported

studied included WC parti-

cle size, binder content

was discussed.

H.M&gxhi et al. (Swmitomo Electric Industries Ltd., ltami, Japan.)

ofLeoben, L&en,

resistance,

pH, of a range of WC-Co

was

carbide

that wear rate is often

Diamond-dispersed carbide material

Effects of carbide additions on corrosion of cemented carbides Corrosion

of cemented

It was noted

debinding,

were investigated.

G.Mori et al. (University

Creep of tungsten alloys under low stresses at 900°C to llOO°C

mechanical

(Indian cermet Sic

cycles, material

Inst. of Technology, and its layered

ftbres were prepared in

H

or vacuum.

had lower porosity.

fibre had lower density

properties.

Structures

and

and proper-

ties were described.

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