What is "hiduminium"

The Hiduminium alloys or R.R. alloys are a series of high-strength, high-temperature aluminium alloys, developed for aircraft use by Rolls-Royce ("RR") before World War II. They were manufactured and later developed by High Duty Alloys Ltd.. The name Hi-Du-Minium is derived from that of High Duty Aluminium Alloys.

The first of these Hiduminium alloys was termed '' 'R.R.50' ''. This alloy was first developed for motor-racing pistons, and was only later adopted for aircraft engine use. It was a development of the earlier Y alloy, the first of the nickel-containing light aluminium alloys. These alloys are one of the three main groups of high-strength aluminium alloys, the nickel-aluminium alloys having the advantage of retaining strength at high temperatures, making them particularly useful for pistons.