Abstract: A die cast, heat treated shaped aluminum silicon alloy article consisting essentially of, based on an alloy weight, from 13 or 25 wt % silicon, from 2 to 6 wt % copper, up to 1 wt % magnesium, balance alumium, said heat treated alloy being formed by the process comprising:subjecting said alloy while in molten condition to a primary pressure die casting at a casting pressure of from about 450 to about 500 kg/cm.sup.2 to form a primary pressure die cast product;removing the primary casting pressure from said primary pressure die cast product;prior to the time said aluminum silicon alloy completely solidifies, subjecting said primary pressure die cast alloy to a secondary pressure die casting so as to reduce the volume thereof from about 1.5 to about 3%;heating the thus treated product to a temperature of from about 460.degree. C. to about 520.degree. C. for a period of time of from about 2 to about 10 hours; andrapidly quenching said product to produce said article.

Abstract: A method of solution heat treating aluminum alloys, especially aluminum-lithium alloys, by immersing the alloy article in a chloride based neutral salt bath rather than in the conventionally used nitrate based salt bath. A chloride based bath, at least in certain controlled situations, produces an effective solution heat treatment but without the staining and corrosive reaction often encountered with the nitrate based salt baths. A chloride based salt comprising 55% potassium chloride, 40% lithium chloride, and 5% sodium chloride is found to be particularly effective.

Abstract: A method of securing a fixing element such as a dowel in a drillhole in a rock mass wherein the element is grouted in position with calcium sulphate hemihydrate plaster (preferably alpha gypsum) gauged with a solution of a water-soluble salt of carboxy methyl cellulose.