Heat transfer behaviour of superalloy droplets during spray forming

-I

Literature Powder production

~36

Fundamentals

~36

Aluminium

~36

Berytium

P37

Cobalt

P37

iron and steel

P37

Nickel

P37

Ceramic materials

P37

Composite

materials

Electrical and magnetic Hard materials Intermetallic Mechanical

materials

and tool steels materials

A.G.Pipe et al. fnt. J Product Research, Voi 38, No JO,

P37

2000, 2201-2214.

P37 ~38

PM components

~38

For copies of full papers you are recommended authors,

to contact individual

use the Interlibrary

Loan

system or, for conference

papers,

to contact the conference

organizers.

Powder production Characteristics of plasma rotating electrode process in preparation of superalloy powder

Equipment for the plasma rotating electrode process and mechanism of powder forming are described. Effects of process parameters on size, size distribution and morphology were investigated. Particle size is also calculated. Particle size decreases as disc rotation speed increases, wirh associated changes in particle size distribution. Good agreement between experimental and calculated values is reported.

Fundamentals

J.F.Sun et al. Acta MetaiLSinica, EnglishEd.. VoJ13,

No 2, 2000, 800-805. A model is described which predicts flight velocity, heat transfer coefficient, solid fraction and cooling rate of superalloy droplets during atomisation. The model is based on Newtonian and heterogeneous nucleation the, ories. The parameters listed are shown to change with droplet size and flight distance. Mechanisms are discussed.

MPR December

A neural network system for modelling mechanical properties of PM parts is presented. The system uses a Bayesian framework and enables prediction of mechanical properties. Accuracy is said to be good for a range of ferrous powder materials and results for two materials are described. In order to optimize process parameters, to meet specified properties, a process ‘advisor’ is developed to be used in recommendation of process conditions.

2001

J.M.h?issiaen.3.Microscopy, Virlf99,No2,2000, 141-148. Use of automatic image analysis in the study of sintered materials is reviewed with regard to the parameters that can he determined. It is reported that the method had been used to measure stereological parameters in WC-Co. The results were analyzed in terms of densification during solid state sintering. Structural evolution and analysis of densification kinetics are discussed.

Reciprocal fracture strength and fracture origin size for hardmetals

Study of sintered materials by small-angle neutron scattering L.Rosra et al. Phystcs B, Voi2761278,2000, 826-829.

Application of small angle neurron scattering, SANS, to study of sintered materials is reviewed. Note is taken of decrease in pore volume and reduction of pore surface area, as measured by SANS. Extension of the method to WC-Co, made from nano-crystalline powders with different types of internal surfaces, is described. Deformation of porosity, remaining after sintering, during further processing can be monitored such as change in bubble shapes during drawing of doped W wire. A new description of mechanisms during thermomechanical processing is established.

Evaluation of degree of sinter in porous PM materials by box-counting technique T.F.Murphy, M.C.Buran.

Heat transfer behaviour of superalloy droplets during spray forming

36

Use of automatic image analysis in study of sintered materials

Use of neural networks to model relationships between process parameters and properties

P37

~38

alloying

Literat

PowderMetail. Sci. Technol.

Fracture properties of high-speed steel, WClOwtO/oCo, Si3N4 materials and Mn-Zn ferrite were investigated. It is reported that K, the intrinsic fracture strength, has a strong correlation with Klc and the size of fracture origin, the effective radius of the tip of microstructural defect that acts as the fracture initiation site.

Application of Stoke’s shape factor in study of sphericity of non-spherical powders. H.Y,Xie, D.W.Zhung. D&m, China.) 2001, 102-10s.

(Dalian Uniwrsrty of Techno&, Powder Tecfmol., Voi 114, No I-3,

Stoke’s shape factor and associated drag coefficient of non-spherical powders were investigated with regard to the flow of nonspherical powders.

Aluminium

Briefs, Vol 2, No 3, 2000,

Development of a test for degree of sinter in porous PM materials is reported. This uses a fracml-like technique, box counting. Digital imaging is used to generate images of pore perimeters on which square grids are superimposed. The number of square boxes touching perimeter pixels is counted. Box size and box count are plotted on a log-log chart and the reciprocal of the slope of the linear part of the curve is defined as the counting dimension. The smaller the slope the more effective is the sintering process.

0026-0657/1x/$

Synthesis and characterisation rapidly solidified aluminium-zinc-magnesium

of

S.U.Din, S.Y.Chishti. (University of Punjab, Lahore, Pakatan.) Powder Technol., Voi 114, No 1-3, 2001, 51, 54. It is reported that AI-35a&Zn-250/oMg powders had been produced by a rapid solidification fine gas jet impingement technique. Powder grain size was 5 to 80mm. Particles less that 20mm were amorphous and partly amorphous

- see front matter 0 z.001 Elsevier Science Ltd. All rights reserved.