Testing and fracture mode of tungsten carbide cemented with iron-nickel-cobalt

PRODUCTION OF NANOCRYSTALLINE IRON-NIOBIUM-BORON ALLOYS A. Kojima et al. (Tohoku University, Sendai, Japan). Mate-r. Science Engng A, A179/ A180, 1994. It is reported that a 99% dense Fe7at%Nb-S’XB alloy had been prepared from powder ground from amorphous ribbon by extrusion at 425”C, 1208 MPa and Sm/sec. The structure was body centered cubic with a grain size of 10nm. Magnetic for these and other extrusion

Hard materials and too/ steels

FORMATION AND PROPERTIES OF ELECTROSPARK COATINGS ON HARD METAL SUBSTRATE

SINTERING OF HIGH SPEED STEEL WITH COPPER PHOSPHIDE AND

V.A. Lavrenko et al. Poroshkovaya Metallurgiya, No 11/12, 1994, 19-24. (In Russian.) A study of electrospark deposition of a W base hard alloy on a Ti alloy substrate is described. It is shown that the structure is modified as the coating is built up. The deposited alloy differs from the alloy from which it was formed having lower hardness and reduced corrosion resistance.

TITANIUM BASED CERAMIC COMPOUNDS M.M. Oliveira, Bradford,

J.D. Bolton.

Bradford,

Preparation

of a composite

and MANGANESE

0.5% graphite,

formation

FOR

phase.

ENERGY

bonded

CONVERSION

ceramic

to

carbides

the

matrix

were

No 3, 1995,239.245.

HIGH TEMPERATURE BETWEEN

energy

IRON-NICKEL

conversion,

is

described.

Use of PM is shown to enhance

properties.

The influence

on electrical thermoelectric Effieciency

of sintered density

and thermal

conductivity

power

is reported

is

and

T.

SILICON

Shimoo

(University

between during

reported

powders

had

that been

Sm-Fe-N produced

100 mesh Sm-Fe powder grinding, heat treatment,

according

annealing.

Effects

on

size,

grain

0

precipitation properties size after increased magnetic

of

of were

process and

clFe

Phases

to conditions

domain

contents, magnetic

size

being

China).

Grain nm, which annealing 300 nm.

0

is shown to enhance precipitation of clFe and a maximum of 9000 ppm is suggested for 0 content. are described.

Magnetic

properties

FERRITES

Japan

Sot.

Powder

Powder

Febut

Ki,,

described.

Vol 13, No 1, 1995,

notch

strain radius.

matrix

correlation

energy Four

identified

fracture

of plane strain fracture

and

of matrix,

discussed, of

TEMPERATURE

and

WC/

BY HIGH

Metall.,

dissociation of Cu oxide in the ferrite. This was affected by milling atmosphere. Non-

composites

oxidizing atmospheres promote separation of the oxide and lead to deterioration of

shown

magnetic

or

MPR April 1996

WC

MADE

Vol 13, No 1, 1995, 88-92.

44

ductile

of WC grains,

SYNTHESIS

electromagnetic properties of Ni-Cu-Zn ferrites was investigated with respect to

ferrite is discussed.

and

CARBIDE-ALUMINA CERAMIC

L. Liquan,

Structure

rate

fracture.

A TUNGSTEN

of sintered

Industry,

Z. Shuge Nanjing,

Studies

and

C

that

particle

gaseous

phases

W can

reactant

be

(Ministry

China.)

are

Light

Z’echnol.,

(In Chinese.) of

WC-A1zOa

elemental

metallic

described. size

are

formed

composition.

of

PM

synthesis

from

reactants and

of

H. Kromp

et al.

(University

of Vienna,

Vienna, Austria). Pokroky Prmkove Metalurgie, No l/2, 1995, 18-33. (In English.) Statistical techniques and linear elastic fracture mechanics were used to predict strength of porous recrystallized SIC. Pore size distribution was measured. A notched four point loading test was used to measure fracture toughness and fractography to show fracture origin points. Good agreement between predicted and measured values is reported. METALLURGY TITANIUM

AND PROPERTIES

CARBONITRIDE

OF

CERMETS

P. Ettmayer et al. (University of Technology, Int. J. Refractory

Metals

SELF PROPAGATING HIGH TEMPERATURE SYNTHESIS OF DENSE SILICON CARBIDE PELLETS

mechanisms

cleavage

fracture

is

was found

release

fracture

Vol 41, No 6, 1994, 681-685. (In Japanese.) Influence of microstructure on

properties.

of

Nanjing,

of WC-lO’X(Fe-N&Co),

A linear

between are

OF

University

Astronautics,

An investigation toughness,

COMPOUND

A. Nakano et al. (TDK Corp, Narita, Japan). J.

and included

Fe and Ni silicides

PM Technol.,

OF CARBIDE

Hard Mate-r., Vol 13, No 6, 1995, 343-351. Reactions occurring during vacuum sintering of cermets are discussed, particularly the system (Ti, MO, W, Ta, Nb) (C,N) (Co, Ni). TiC is shown to dissolve in liquid (Ni,Co) leaving TiN. Gases evolved were investigated and with the results of differential thermal analysis improved understanding of sintering mechanisms. Property/structure relationships of cermets are discussed with regard to the C:N ratio, stoichiometry of hard phases, composition and proportion of matrix and cutting ability. Examples are given.

varied

(In Chinese.)

intergranular

EFFECT OF MILLING CONDITIONS ON PROPERTIES OF SINTERED NICKEL COPPER-ZINC

3843.

and

SILICON

formed

(Nanjing

et al.

Aeronautics

OF STRENGTH

RECRYSTALLIZED

Vienna, Austria).

WITH IRON-NICKEL-COBALT

N

IO-30 after

heat

from

and

Fe-Ni

not Fe or Ni nitrides.

T.Guoquan

PREDICTION

in Ar or N, were

TESTING AND FRACTURE MODE TUNGSTEN CARBIDE CEMENTED

conditions

determined.

milling was to 50 nm

and

alloy

by mechanical nitriding and

Osaka

J. Japan

isothermal

Ni-Si solid solution, M. Ito et al. (Osaka University, Saito, Osaka,

of

Si3N4

at 850.13OO”C,

investigated.

Japan). J. Japan Inst. Metals, Vol 59, No 6, 1995, 666-672. (In Japanese.)

AND

Metals, Vol 59, No 4, 1995, 415-422.

treatment BY

REACTIONS

Sakai, Osaka, Japan).

powders, NITROGEN POWDERS PREPARED MECHANICAL GRINDING

interfaces.

ALLOY POWDERS

Reactions

OF SAMARIUM-IRON-

type

(In Japanese.)

over a range of densities. PROPERTIES

at

NITRIDE

et al.

Prefecture, Inst.

discussed.

to be satisfactory

well

MC

with TiOs were porous.

of Fe and Mn silicides, for

thermoelectric

were

and

detected

Composites

by

phosphide

particles

E. GroB (University of Karlsruhe, Karlsruhe, Germany). Int. J. Powder Metall., Vol 31, PM processing

Sintering

and was activated

of an Fe rich liquid

The

HSS

7wt%CusP

is reported.

was at 1140.1170°C

OF IRON AND

SILICIDES

THERMOELECTRIC

of

Metall.,

M2/3

with Tic, TiN or TiOs particles,

POWDER METALLURGY

is

Powder

Vol 38, No 2, 1995, 131-140.

properties conditions

are given.

It

(University

UK).

of

It

is

reactants,

important. according

WC to

R. Raghunathan

et al.

(North

Carolina

State University, Raleigh, North Carolina, USA). Mater. Man@ Processes, Vol 10, No 3, 1995, 559-563. It is reported that SIC had been synthesized in Si-C pellets by a self propagating high temperature reaction using Ti as a binder. Effects of Ti on the synthesis was studied and it was found that the synthesis incubation time was reduced and the reaction rates for Sic and TiC were increased. TiSia was not detected. A model for the process was devised. ANALYSIS

OF THERMAL

STRESS

IN

COMPOSITE SILICON CARBIDETITANIUM CATBIDE-NICKEL SYSTEM J. Hojo et al. (Kyushi University, Japan).

J.

Japan

Sot.

Powder

Fukuoka, Powder