Preparation of tungsten-copper from mechanically and chemically activated powders

It is reported

that Sic

powders had been

added to the spray during spray forming of two steels. Use is made of a device that injects the Sic

powder into the atomisation

spray to ensure

thorough

metal droplets. Structures

zone of the

mixing

with

the

and properties of the

two steels were investigated.

Preparation of tungstencopper mechanically and chemically activated powders .I..ChenRchnng

rl

al.

(Univervty

of

Sintering and structural nickel aiminide-titanium cermets

from

Science

nnd

TechnoJqy, Brrjmg, Chma.) PM Technolog, Vol 19, No 3, ZOOI, 148.152.

In Chinese.

It is reported that W-Cu alloys had been sin-

tered from powders that had been mechanically

Tungsten

and chemically

Characterisation of particle ultrafine tungsten L.Jrqm,

H.Baiyun.

TechnoJogy,

(Central

size of

Int.

of particle

range of as-received

on a

due to defects in

which

sub-sieve

were laser dif-

sizing

and

BET

methods. It is considered that these are due to failure to take surface condition account.

A

modified

and pores into

method

giving

better

results is proposed.

Strengthening mechanisms in tungsten heavy alloy processed hydrostatic extrusion Z.Zhmhui. WFwhi.

Properties processed forming

which had been hydrostatically investigated

extruded, were

with the object of discovering

strengthening

mechanisms.

function

of deformation

densities

in matrix

the

W contiguity,

direction,

as a

dislocation

and W grains, aspects of

sub-grain structure in the W grains and effects of change

in extrusion

ratio are considered.

W’.B.IIurt al J.Jqmn

Sm.

(Umwrsity

2000.1073-1079.

Mechanical

properties

and

structures

of

AIZO, wire and fihre, made by controlled

frac-

ture

It is

forming,

CR,

were

investigated. mechanical

properat

ment of metal matrix composites.

Fabrication of compositionally graded silicon carbide-carbon material

Elemental

W-7%Ni-3%Fe

mechanically

alloyed,

mixed

polymer binder, injection and sintered.

Structure

investigated

to

conditions.

shown

to enhance

to full density grain

mechanical and milling

the

const>lidation.

at 1350°C 2 to

a waxdebound

properties.

were

effects

of

alloying

is

Sintering

A.H.Wu Bepq,

facing

Vol J I, No J

2OOJ , 23-26.

In Chme,e.

Compositionally

graded

Sic-C

materials

were produced by hot pressing. B and C were enhancers.

The

material

to thermal

shock

and to be

et al. (Banloche Atmmc Centre, Argentina.)

PowderMrmll., Vo143, No 1, 2000. 83-88. It is reported

that composites

of Al or AL-

type

stress could be estimated.

The AI-Cu material

was

WRS similar for processing

below the eutectic

from

Konopicky

grain

porosity

of 15Pa due to liquid phase mechanism,

MPR March

had a

There

milling time that resulted in

strength.

in

temperature,

548°C.

Above

this

the

model only applied below pressures attrib-

uted to diffusion of Cu from liquid to solid Al.

2002

effects of sintering temperature. Composites with ahove 60~01% alloy showed a marked increase in fracture toughness, which was up to lOMPa.m-l/2 for pure PSZ.

Evaluation of wetting of silicon carbide by molten aluminium (Sumitomo Elccmc ImJustrie~ Co. 1056-1060.

In Jufmnex.

Wetting effects in AI-Sic are discussed and were investigated by Hg porosimetry and pore size analysis. Increase in temperature

increased

open porosity and pore size causing high wettahility. Addition of a small amount of Mg increased wettahility, decrease in surface tension is needed to improve wettahility.

Fabrication of particle shape memory alloys H.Muraoku.

dispersed

(Tokyo Sot.

JOhJ-1066.

Denkl

Uniuersq

Pow&~/J’owderMrtal1., JnJqmnese.

It is reported that attempts had been made to

fabricate a material comprising particles of TiNi in a steel matrix by pulsed electric current sintering. The XNi particles were uniformly distrihuted and not deformed during processing.. Density was 95%. There was diffusion of Fe into the TiNi and there was dissociation of TNi at

model and yield

of ball

reduction

and

to study

he more satisfactory than in conventionally sintered material due to shorter sintering time giving thinner interface zones.

was applied for various times. For the Al mate-

and at extended

and

determined

particle surfaces. The structure is considered to

short fihre reinforcements

rials the density/ pressure relationship

balls

properties

had

Cu with Al,O,

contamination boundary

mechanical

of both were

sintering

been made by hot pressing. Maximum pressure

good fit with the Konopicky

steel

alloy and composites

prepared by plasma activated

Vol47, No IO, 2000,

gave

stainless

Samples of PSZ, partially stabilized ZrO2, a Ni-G-AL-Y

Saitama, Japm~.) J.Japm

good

Effects

is

Hot pressing of aluminium- or aluminiumcopper-alumina short-fibre composites M.EMormo

of

to be free from cracks and to have

to 1450°C

are discussed.

was detected.

et al. (Hmyan~ L’nwersrry, Seoul. Korea.) J

Vol47, No JO, 2000,

et al. (Uniwrsity of Sc~mcr and Tcchnolo~,

China.) PM J&my,

5mm

and

TIC grain size increased with increases in %Ni,Al and process temperature. TC showed a

T.Asaoka,

were

and properties

Mechanical

size of time

with

moulded,

determine

process

powders

hy use of contents.

Ltd., Immi. Japnn.) J.Japnn Srx. Pou’~r/PozvdrrMetail.,

Composite materials

3, 2000, 13-16.

was inhibited

at higher total Ni,AI

C.Kuwa~. Y.Tak&

resistant to nuclear irradiation.

PM SciencelTechnol. Briefs, Vd 2, No

Chamha, China.)

pressing. Densification Ni and NiAl

above

this. The wire and fibre is used for reinforce-

good resistance

54

No JO,

In En&h

reported

a W

of Tokyo, Tokyo, Japm.)

Pozu~r/J’o~ld~rMetall., Vol 47,

used as sintering

of Technolom,

applica-

tions. Compacts were fabricated by pressureless sintering followed hy low gas pressure isostatic

UP&k

mining strength.

.l.Fan et ul. (Cmtrrtl South L’nwmty

composites are

for diesel engine

Alloy.ComJ>d., Vof 313. No J-2, 2000, 248-257.

These are shown to he the main iactors deter-

Effects of mechanical alloying on structure and properties of tungsten heavy alloy

It is reported that Ni,AI-TiC

under development

Mechanical characterisation ceramic-alloy composite

of alumina wire by controlled fracture

less than 2% porosity and intergranular

of W heavy alloys,

and properties

Laboratory, USA )

in mm, and preferred orientation

177-182.

Structure

(Oak Rldfil’Natwal

Jnr J. Powder Meull., Vol36, No 7, 2000, 46-57.

core-rim structure. Grain size of Ni,AI was large.

ties. Fracture is reported to be transgranular

(Beljmg Inst. of TechnoJqy, Be&q,

rt al

in

Ceramics

shown that CFF enhances

by

Chmn.) Inc. J. Refmct. Metals/Hard Mnter., Vol 19, No 3, X01,

bility of Cu in W. High density was attained.

Refract.

size measurements

methods

Fischer

J.

and milled W powders are

shown to reveal discrepancies fraction,

ders ensured fine particle sizes and homogeneous

89-90.

MetulslHurd Mawr., Vi1119, No 2, 2001,

measurement

and prop-

distrihution of W and Cu. There was some solu-

South Unwersity of

China.)

Chanpha,

Studies

activated. Structures

erties were determined. Preparation of the pow-

JI.L.Baker

evolution carbide

In situ synthesis of titanium carbide and titanium diboride in iron aluminide B .G .Park er al. (-i%hukuNatwmJ l&.miaJ

Research 1~. ,

Senndm, jqxcn.) J.Japan Ser. Pr,w&r/PowderMet., 47, No JO, 2000, 1080-1084.

In En&h.

www.metal-powder.net

Vr,J