Method of heat treatment of Al-based alloys containing Li and the product obtained by the method
US4812178A · kind A · utility
Inventor
Key dates
| Filing date | Dec 5, 1986 |
| Grant date | Mar 14, 1989 |
| Priority date | — |
| Expiry date | Dec 5, 2006 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC22F1/04
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
The invention concerns a method for final heat treatment ageing of Al alloys optionally containing Li and at least one other major element selected from the group Cu, Mg and Zn, as well as possible minor elements such as Zr, Mn, Cr, Ni, Hf, Ti and Be, in addition to inevitable impurities such as Fe and Si. The treatment involves a principal ageing operation which takes place at a time and temperature in an area defined by a parallelogram on a temperature log-time diagram, whose corners have the following coordinates: A 270.degree. C.-3 min; B 270.degree. C.-48 min; C 225.degree. C.-9 hrs 30 min; D 225.degree. C.-35 min. The heat treatment makes it possible to produce a satisfactory array of mechanical characteristics such as mechanical strength, ductility, or toughness and resistance to corrosion, which are higher than those achieved by means of conventional treatments of type T6 or by under-ageing operations.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.