Microstructural evolution in ball milling of nickel aluminium titanium

It is reported W-C

that use of specially

powder,

powder,

instead

had allowed

WCC0

materials.

mation

production The

of triangular

was investigated. tening

of W

formation

of W-C-Co

crystallographic solid

state

grains

in

WC

during

grains to flat-

ball

milling,

die compaction,

intermediates,

relationship

heating, presence

with

to WC

and

a

during

collapse

of

of

a W-C-Co

liquid

K.Isonwhi, M.Asano.

by

hours

had

a Ti/Si

1000

hours

there

627°C

for powders was more

in a 1:l

ratio,

investigated

with

properties. The and

330

and

than

was

to structure

and

fracture

TiAl,

IOO-hour

phase

with

strength

1350MPa

The

sintered

a

hardness product

with

is

a Ni-Al

additive.

er density. spherical

ration

solubility tice

parameter

were

mechanically

the supersaturated

95%

was

25at%.

at 1.4GPa

and Vicker’s

hardness

of 121.

powder had 96.3%

density

of

compacted

and hardness

from lat-

compacted

Impact

Solid-state reactions in mechanically alloyed magnesium-silica A.Yamazaki et al. (Nihon University, Narashino, Japan.) J.Japan Sot Powder/Powde~/Metall., Vol 48, No 1, 2001,6 J -66. In Japanese. powders

alloyed

together

pressed.

Reactions

powders

and sintered

tigated.

It

44

was

in

Ar

were mechanically and

between materials

found

MPR October

that

2002

regard

to pore sizes and distribution

Milled

depended

on

materials.

Pores

under was a

594°C 1000

to

hours.

heating

and

hours attained

the

high-

is attributed

to

are discussed

findings

vacuum Mg

and were

the

of ordered

by

very

in dried

by promotion

in atmosphere

of moisof diffusion

products.

is essential

Presence for

of

complete

debinding.

fine

Digital in situ measurement of uneven shrinkage in PIM compacts R.Watanabe et al. (Tohoku University, Sendai, Japan.) J. japan Sot Powder/Powder/Metall., Vo148, No 1, 200 1, The problem ing sintering

intermetallic is noted.

several

materi-

This

NiAl

can

be

including

of long range ordering

by incorpo-

phases

phase.

Grain

methods

phases.

a composite Long

with

and

A ternary

milling

characterised

Rietvald’s

powder

Ni-Alof pro-

NiTi

and

Ni-Al-Ti

alloying

Structures

were

ordered

a disordered

mechanical

these phases.

at different

formed stages of

and analysed

structure

by

refinement

methodology.

shrinkage

sintering

is noted.

It is reported

imaging

technique

had been

that a digital used in situ to

measure this in two dimensions tact basis in real time. The experimental that

than

attributed

on a non-con-

method

results are described.

shrinkage

greater

beneath below

and some

It was found

a curved

a plane

to differences

dur-

moulded parts during

surface

surface.

in packing

This

is is

density.

Development and challenges injection moulding

of

Y..f.Cao. (Central Iron/Steel Research Inst., Beijing, China.) PM Industry, Vol 11, No 3, 2001, 7-17. In Chrnese Advantages

and limitations

tion

moulding,

PM

and

Potential cost

compared

investment

of powder injec-

with

casting

conventional are

reviewed.

for growth and challenges,

effectiveness

including

and attainment

of dimen-

are considered.

Powder injection moulding Miscellaneous

Characterisation of waterand gas-atomised SS powders for MIM

Automation

D.Rodrigues et al. (Inst. Pesqui. Tecnol. Estado, Sao Paula, Brazil.) PM SciencelTechnol. Briefs, Vol 3, No I, 2001,14-17 Parameters

affecting

and gas-atomised

hot-

moulding, discussed

inves-

of non-uniform

of injection

sional precision,

SiO,

products

proceedures

of 0 and decomposition

with

, which

due to evaporation

ture aid debinding 0

into pipes.

were investigated

mixing

and cellu-

in the

had a

of 200.

Mg and SiO,

After

The

of disordered

ducing

measurements,

density

for

had been extruded

at heating

Ti alloy was made with the intention

of C in the Cu, determined

Powder statically

and debinding

densification

during

brittleness

reduction

et al. (Hiroshima Inst. of Technology, Hwshima, Japan.) J.Japan Sot Powder/Powder/Metall., VoL48, No 1, 2001, 9-14. InJapanese. that

Drying

with Al and Ti are reviewed.

improved

T.Yamane

It is reported

lose feedstocks

M.De et al. (Indian Assoc. for Cuftioation of Scrence, Cakutta, India.) Mater. Chemistryll’hyws, Vol 72, 2002, 167-176.

Impact consolidation of mechanically alloyed copper-carbon powder

alloyed.

milled

of metal

propyl methyl

100

Microstructural evolution in ball milling of nickel aluminium titanium

boundary

powders

at

a range

for

up to 1000°C density

that

powder/hydroxy

powders

in terms of superplasticity.

Mechanical alloying

C

hot pressed

rapid

This

Properties

and

structure.

for 1000

grains.

als of Ni

Cu

lamellar

in

powder milled

ceramic

82-86. In Japanex.

Ti3Al

Vicker’s

was brittle.

material

milled

of 1OMPa to ZOOMPa. There increase

powder

of

was attained.

Ti-Al-Co

but the material softer

powders,

density

size of 20 to 25nm.

CoTi,

comprised

a solidified

with

Ti-37.5at%Si

of 20degC.min-1

sudden

elemental

Co

respect full

structure

grain was

Near

of TiAl,

and

of techniques.

1,

It is reported

was amorphisation.

There

Al,

by a range

powder is shown to be the more

K.Ikeda et al. (Tohoktr University, Sendar, Japan.) J .Japan SK Powder/Powder/Metall., Vol48, No I , 2001, 3-8. In English.

No

sintering,

Powders

were vacuum

A.Hibino, S.Matsuoka. Uniwersity of Toyama Prefecture, Toyama, Japan.) J.J@an Sot Pcwder/Powder/Meta11., Vol 48, No 1, 2001, 69-76 In Japanese.

rates

Vol 48,

pressure

alloyed

investigated.

pressures

from

Gas-atomised

(Shiga University, Otsu, Japan.)

Densification,

materials

additive,

were characterised

Drying and debinding of extruded pipes with a water soluble binder

Combustion synthesis of dense TIAJ with COAI sintering additive

sintering

and

heating

Mechanical alloying and densification of titanium-silicon powders

powders

Al

MgO

after

suitable.

mechanically

synthesis

and

at 500°C.

was

Combustion

Mg2Si hardness

J.Jagan Sot PowderlPowderlMerall., 2OOJ,77-81. In Japanese.

WC

ph ase.

Intermetallic

were

in increased

of for-

is attributed

during

in situ

resulted

of superior

prismatic

particles

of these

formed

WC

mechanism

This

orientation

prepared

of conventional

Waterpowders

notably

the suitability

metal

particle

size and shape, are

with regard to density and gas-atomised and

injection

of water-

powders for injection

316L

of compacts. stainless

moulding

steel

feedstocks

in PM operations

H.Hjort. (Jnnouata Inc., Fair&Id, USA.) .) PM SciencelTechnol. Briefs, Vof 3, No I, 2001, 23-26. Matters mentation tion

involved

operations

siderations

with planning

of automation

are discussed.

are illustrated

of a press-to-furnace

and imples

in PM parts producTechnical

through

system.

made for close co-operation

con-

a description

A strong

case is

between

automa-

tion system maker and parts producer

to define

the optimum

system for a given situation.

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