Fine-grained sintered molybdenum processed by mechanical alloying

particle

morphology

is not

altered

during

housings

were reviewed.

and evaluated

granulation.

Samples

for shape

were made

and properties.

was shown that powder injection

Multicarbide

allowed

hardmetals

O.N.Eiduk et al. (Research and Design Inst. fo7 Refmmy and Hardmetals, Moscow, Russia.) Structures lO)wt%Co

and

properties

with S%TaC

were investigated.

or

The materials had an ultra-

fine grain structure, hardnesses

of WC-(6

and 0.4 to lO%VC

0.2 to 0.5mm.

in the range

Vicker’s

1600 to 1750 were

reported.

net-shape

ties and highest

density

was found for Mo-

Production of sub-micron powders by chemical reduction from aqueous solutions

make nano-crystalline

WC-Co,

without

rial was encapsulated temperatures

the

The mate-

in glass for HIP. Lower

were required to reach the closed

porosity stage than in conventional Fully dense WC-(10 duced at 1000°C

processing.

to lZ)wt%Co

to 1200°C

was pro-

in 30 minutes at

15OMPa. The role of HIP in activating

densifi-

cation was discussed.

Graded tungstencopper

including

homogeneous method

powders, powders of

solid solutions,

persion-strengthened

W-Cu

materials and

compaction Structures

were investigated

were used in

and composition with

reference

to

was shown to be applicable

Fabrication of titanium-nickel-copper shape memory alloy powders by ball milling

and

Ti-Ni-Cu

powders

20 hours

of elemental

Ti and Ni powders

which reacted on heating.

After 20 hours the

powders were solid solutions

of TI in Ni and

Ni in Ti which did not react during heat treatment. Ti-40%Ni-lO%Cu

could be alloyed by

milling for 30 hours at 100rpm.

of more than 2%W

or MO. by

of cored structures.

Injection moulding of tungsten- or molybdenumcopper materials for microelectronics

methods

for making for

www.metal-powder.net

W-Cu

microelectronics

parameters

contact

fatigue were investigated.

Effects

of

on rolling Effect of sur-

face finish was tested on as-sintered and ground samples. The paper reported on contact of various alloys as a function

fatigue

of surface densi-

fication. High values were obtained for shallow surface den&cation.

Effects of microstructural inhomogeneities on fatigue of PM steels A.Lawley et al. (Drexel University, USA.) Effects

of microstructural

on fatigue properties including

hybrid and

it-homogeneities

of a range of PM steels,

grades,

material

were

investigated.

parameters

were

impact and fatigue proper-

ties were measured and evaluated

with regard

and pore morphology.

H.Kurishita et al. (Tohoku University, Ibaraki, Japan.)

been prepared from mechanically

alloyed pow-

ders by HIP or spark plasma sintering.

There

was no grain growth at 2200°C after 1 hour due to grain boundary pinning. The ductile/brittle tensile

temperature

strength

was reduced

was increased.

and the

The

changes

to the fine grain structure and

Effects of core carbon content on rolling contact fatigue J.Petersen, P.Beiss.(Technical University of Aachen, Germany.) The importance

of resistance

to rolling con-

tact fatigue of sintered parts was emphasised. It was reported

that a machine

for testing

investigate

Distaloy HP1 with various C con-

tents at density of

7.lgm.cm-3.

C.Sfat et al. (POLITEHNICA Universiy of Bucharest, Romania.)

Mechanical alloying

solidified by melt spinning, gated with consideration Cooling

rates

106degCsec1. tive component

were

alloys,

rapidly

had been investi-

of process conditions. of

the

order

of

The alloy has uses in automoproduction.

The

results

showed that endurance reached a maximum at 0.2%C.

of Al-8%Fe-2%v-l%Si

for

rolling contact had been developed and used to

Structure of rapidly solidified aluminium alloys

erties

and

to improve

published.

and material

to microstructure

It was reported that the structures and prop

M.Kniiwer et al. (Fraunhofer Inst. Manufactuting and AdvancedMaterials, Brement, Germany.)

had been

described. Tensile,

and this

was accompanied

fatigue, many

surface den&cation

process

Process

Fine-grained sintered molybdenum processed by mechanical alloying

were attributed

refinement

ous papers about rolling contact

were ball

powders milled for less than

grain boundary strengthening.

required addition

Surface pitting of sintered parts, as a failure mode, was reviewed. It was noted that numer-

performance,

cal contacts had been made from coarse Cr and require refinement

PBlanchard er al. (Federal Mogul Sintered Products, USA.)

als like Au, Ag, Pt and Pd.

fine Cu powders by liquid phase sintering. The large Cr particles

Effects of processing on rolling contact fatigue of PM materials

concerning

transition

Seoul, Korea.)

It was reported that Cu-Cr alloys, for electri-

materials

to base

It was reported that fine-grained sintered MO

M.J.Kim et al. (Uniuersiq of Seoul,

MO-Cu

The

with fine dispersed particles of ZrC or TaC had

Microstructural evolution in copperchromium alloys during liquid phase sintering

Process

powders.

use in fusion reactors

process parameters.

formation

and oxide-dis-

alloy

Fatigue strength

metals such as Cu and Ni and to precious met-

still consisted

and use of PM in making parts. Die and con-

The particle

of metal

milled to study alloying and transformations.

were reviewed with regard to properties

making compacts.

sible to produce elemental

Ti-Ni

materials

graded

centrifugal

of metal powders by addition of a

ions was reviewed. It was shown that it is pos-

Ti-Ni

M.Joensson, B .Kieback. (Dresden University of Technology, Dresden, Germany.)

applications

of

S.H.Kang, T.H.Nam. (Gyeonsang National LJniue&y, Korea.)

High performance PM materials

Compositionally

University

reducing agent to aqueous solutions

It was reported that HIP had been used to addition of grain growth inhibitors.

parts.

33%Cu.

Production

ECastro et al. (University of Nawarra, San Sebastian, qxlin.)

profiles

of

Coarse W-Cu powders gave the lowest densi-

C Edtmaier LienC.$iz;,jWienna Technology,

Hot isostatic pressing of nanosized tungsten carbidecobalt

tinuous

production

It

moulding

Effect of nickel addition on mechanical alloying of iron-zirconium-boron powders Y.Liu, I .Chang. (Universityof Birmingham,UK.) Mechanical erence

alloying was discussed with ref-

to methods

and effects

MPR May

on materials

2002

39