Precipitation hardening defined

Non-Heat-Treatable Alloys. Non-heat-treatable aluminum alloys are defined primarily by what they are not. They are not strengthened by second-phase particles and may be better described as non-precipitation-hardening alloys. The non-heat-treatable alloy classes are the Ixxx, 3xxx, and 5xxx alloys. 

It is rather difficult to exactly define the meaning of the word composite . In the broadest sense, one might consider every material as a composite that comprises two physically distinct phases. However, using this definition would imply that almost every technically used material is a composite, for example almost all steels or precipitation hardened alloys, rendering the definition practically useless. Composites used today are characterised by the following properties ... 

The MUF resin pH was determined using pH meter model pH 340-A/SET l-MTM. The pH meter was calibrated before it was used to determine the pH of the resin. The viscosity was determined using the Cole-Parmer 98936-15 viscometer (R2 spindle, lOOrpm speed). The storage life was a test of shelf life of the MUF resin under the ambient environment. Resin was first stored at ambient room temperature. Viscosity of the resin was checked for every three to four days. The ratio of water that can be added into resin before it turned turbid or precipitated is called resin solubility. The resin solubility was determined by divide the weight of resin and the weight of water added into resin before it turned turbid or precipitated. The curing period of a resin was defined as the time period for the resin to be hardened after application in a 30°C and 1.0% of NH4CI powder (as hardener). 

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