The effect of oxide layers on gas-generating hydride particles during production of aluminium foams

Book · Thu Dec 31 04:00:00 EST 1998

OSTI ID:361812

Gergely, V; Clyne, T W ^[1]

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1. Univ. of Cambridge (United Kingdom). Dept. of Materials Science and Metallurgy

Melt routes to metallic foam production offer attractions of low cost and the potential for good microstructural control. In situ gas generation may be preferable to external gas injection in terms of the important objective of generating a fine and uniform cell structure. The main difficulty with this approach has been that of ensuring that the gas-generating powder is suitably dispersed throughout the melt before the gas is released and the cells are formed. In the present paper, procedures are outlined for preparation of powders for use in aluminium melts, where gas will be released only after a suitable delay, allowing the powders to first become well-dispersed in the melt and solidification to start. Pre-treatment of the foaming agent also facilitates a flexible production of castings with various porosity at the same processing conditions simply by varying the thickness of a diffusion barrier layer on the gas-releasing agent. The role of the melt viscosity history, as a function of a heat extraction rate from the solidifying melt and an alloy composition, on the final porosity of the castings is also briefly discussed.

• OSTI ID: 361812
• Report Number(s): CONF-980405--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM BASE ALLOYS
EXPERIMENTAL DATA
FOAMS
GAS FLOW
HYDROGEN
LIQUID METALS
MANUFACTURING
PORE STRUCTURE
TITANIUM HYDRIDES
TITANIUM OXIDES