Method for thermal processing alumina-enriched spinel single crystals
A process for age-hardening alumina-rich magnesium aluminum spinel to obtain the desired combination of characteristics of hardness, clarity, flexural strength and toughness comprises selection of the time-temperature pair for isothermal heating followed by quenching. The time-temperature pair is selected from the region wherein the precipitate groups have the characteristics sought. The single crystal spinel is isothermally heated and will, if heated long enough pass from its single phase through two pre-precipitates and two metastable precipitates to a stable secondary phase precipitate within the spinel matrix. Quenching is done slowly at first to avoid thermal shock, then rapidly. 12 figs.
- Issue Date:
- OSTI Identifier:
- 46308
- Assignee:
- Dept. of Energy, Washington, DC (United States) PTO; SCA: 360601; PA: EDB-95:077898; SN: 95001384501
- Patent Number(s):
- US 5,413,973/A/
- Application Number:
- PAN: 8-190,940
- Contract Number:
- AC09-76SR00001
- Resource Relation:
- Other Information: PBD: 9 May 1995
- Research Org:
- E I Dupont De Nemours & Co Inc
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 36 MATERIALS SCIENCE; SPINELS; HEAT TREATMENTS; ALUMINIUM OXIDES; MAGNESIUM OXIDES; OPTICAL PROPERTIES; MECHANICAL PROPERTIES; MICROSTRUCTURE; MONOCRYSTALS