Sintering features of tungsten carbide-cobalt processed from fine powders

Sintering features of tungsten carbide-cobalt processed from fine powders

Copper yield stress and critical Studies of copper-based memory alloys shape Shape were memory properties investigated improving mates. of Cu...

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Copper

yield stress and critical

Studies of copper-based memory alloys

shape

Shape were

memory

properties

investigated

improving mates.

of Cu-based

with

the

performance

some with additions

to

of

in cold

3.5)Ni

cli.

alloys,

of Ti, B and C, were stud-

ied. Ti, B and C increased alloy and lowered

alloys

objective

for use

Cu-13.9%Al-(3.2

and increased

alloys showed

reduced

critical

Y.Suzuki et al. (Hokkaido National Industrial Research inst., Sapporo, Japan.) J.Japan Sot. Powder/Powder Met&., Vol47, No 8, 2000, 830s837..lapnnere.

the strength

the shape memory

of the

transition

Initial stages of sintreing

of nano-crystalline were

Fe,

Fe powder

steady

state,

reached.

during

investigated.

coarse

With

refinement

further

an

is gradual

milling

and a

grain

is

boumdary

relaxation was detected. It was deduced that nano-crystalline materials, with the same grain size may exhibit on

the

differing

properties

microstructure

metastable

of

the

depending numerous

in real powder

and properties

from

that steel foams had been pro-

Fe-2.5%C

MgC03

or

Densities

were

were carried Heat

tion,

changing and

as the

38 to 64%.

with

0.2wt%

foaming

agent.

Mechanical

out to determine

tion ferrite

powder

SrC03

treatment

energy

resulted

the range

absorp-

that

of particle

from

the ductile

pea&e

to

response

to

agglomerated ment

alloy powder

made by heat treat-

and from pulverized

alloy powder.

The

the best performance.

Preparation and use of magnetic fluids S.L.Liu et al. (Central Iron d Steel Research Insr., Beijing, China.) PM Industry, Vol IO, No 5, 2000, 3239. In Chinese. Methods

of making

metal

oxide,

Fe4N

powders

described. bearings,

metal

magnetic

and

and

operating

Applicadons grinding

fluids,

compounds

from

such

principles

as

were

of such fluids in seals,

and damping

were discussed.

Hard materials and tool steels

M.Rosso et al. (P&technic ofTorino, Torino, It&.) ht. J. Refracr.Met&/Hard Mnter.,Vol 19, No I, 2001, 45 52. to improve

of parts was discussed coating.

Studies

thermally

stainless

with reference

rosion

resistance

The coatings

coatings

3 or on 416

with a Ni-Cr

The coatings

bond

SLuyckx et al. (University of Witwatersrand, Johannesburg, South Africa.) int. J. Refracr.MetnIs/Hard Mater.,Voi 19, No I, 2001, 41-44. Investigations of the effects of up to 3wt%Ru added to WClO%Co are described. It is shown that

the hardness

reduced inhibitor

of WC

abrasion

resistance

binder

is increased

and

as the %Ru is increased.

high cor-

and acid solutions.

were characterised

Effect of ruthenium on hardness, toughness and grain size of tungsten carbide-cobalt

are shown

and to confer

in saline

to

the effectiveness

sprayed

to have good adhesion

resis-

of A1203-(0,

steel pump pistons,

layer, were described.

corrosion

grain

growth

due

toughness

Ru is a weak and

improves

to hardening

of the

phase.

by microhard-

ness and microscopy.

Sintering features of tungsten carbide-cobalt processed from fine powders

in decarburiza-

the structure

increasing

tests

were

Corrosion resistance and properties of pump pistons coated with hard materials

13)TiO2

duced

systems

of 3 Ag-I’d

Coatings

of the

288, No 1, 2000, 111-118.

data

It is emphasized

the effect of pores in reducing

of

S.R.Nutt, C.R.Pnrk. Mater Science/Engineering A, Vol

It is reported

the degree of densi-

sizes must be considered.

tance

PM synthesis steel foams

this is

that as the proportion

with a model.

properties

and

in situ

to correct

and electrical

last of these showed

is shown

Experimental

Use of coatings

grain boundaries.

Physical

of large

radiance

increased

pastes from powders

pastes, for use as electrodes in multilayer ceramic devices, were investigated. The pastes were made from co-precipitated powder,

compacts

using

errors and means

decreased.

compared

size range,

proportions

It is reported

of large particles

initial

Silver-palladium

of A1203

Sample

Electrical and magnetic materials K.Koumoto et al. (Nagoya University, Nagoya, Japan.) IJapan Sot. Powder/Powder Metall., Vol 47, No 8, 2000, 844-852 In English.

was investigated

dilatometry.

fication

mechanical

in the nm particle

On

different

particles

to introduce

Y.H.Zhao et al. (Chinese Academy ofSciences, Shenynng, China.) Acta Mater., Vol49, No 2, 2001, 365-375. Structural evolution and thermal properties

and lower

up to 50Cppm.

R.A..Dorey et al. (University @‘Surrey. Guildford, UK.) Acta Mater., VoI 49, No 3, 2001, 519-527.

described.

Structural evolution and thermal properties of iron during mechanical attrition

yield strength

at

Mo-Pd

In situ dilatometric measurements of initial stages of sintering of alumina

optical

Iron and steel

decreased

at 830ppm.

Ceramic materials

small

alloying

temperature

containing

temperature.

temperature

up to 6lCppm

Composite materials

spite of larger pores in the steel.

Multistage sintering for preparation of nickel aluminide-alumina composites

C.H.Allibert. (CRNS-INPG-UJF, St-Martin d’Heres, France.) ht. j. Refracr.MetalslHnrd Mater..VoI 19, No I, 2001,53-61. Use of increasingly fine powders to make WC-Co

Molybdenum

W.C.Chiou, C.T.Hu. (National Tstng Hua Unierersity, Hsinchu, Taiwan.) Metall. Mater. Trans A, Vol 32, No 2,2001,407-415.

between

compressive ty between

loading.

There

was some similari-

the ferritic foams and those of Al in

Low-temperature fracture of molybdenum with small additions nickel or palladium

Production

of

N.Yosizawa et al. (Okayama University of Science, Ok~~yama,Japan.) J.Japan Sot. Powder/Powder Metall., Vol47, No 8, 2000, 824-829. In Japanese. Low temperature with additions investigated. the grain with

fracture

properties

of up 9GOat.ppm It is reported

size and that

increased

alloy

of MO,

Ni or I’d, were

content.

www.metal-powder.net

with

elemental

powders

of

Ni-24at%Al-O.l%B

5 or

lOvol%A1203,

and

B is described. compacted, further

heated deformed

transient formed

The

liquid

phase

and provides

coated

powder

to to

A1203 a low

with

is canned, temperature,

eliminate

pores

sintered.

the liquid

from

phase.

of 14.6 and 8.9%

attained

10%

with

respectively.

Ni alloys

5 and

A1203

and

differences

in

densification

microstructural

mm and nm size particles

evolution are noted.

In the case on nm size powders the large contribution to solid state densification and abnormal grain growth are considered. Factors related to hindrance of densification and grain growth inhibition are identified.

is

Mechanical alloying

In ten-

sile tests elongations for

and

and

Ni2A13

stress decreased

that Ni and I’d refined critical

composites

behaviour

were

materials

Effect of ball-charge fraction on mechanical alloying in vibratory ball mill

MPR

January 2002

37