In 1906, precipitation hardening alloys were discovered by Alfred Wilm. Precipitation hardening alloys, such as certain alloys of aluminium, titanium, and copper, are heat-treatable alloys that soften when quenched (cooled quickly), and then harden over time. After quenching a ternary alloy of aluminium, copper, and magnesium, Wilm discovered that the alloy increased in hardness when left to age at room temperature. Although an explanation for the phenomenon was not provided until 1919, duralumin was one of the first "age hardening" alloys to be used, and was soon followed by many others. Because they often exhibit a combination of high strength and low weight, these alloys became widely used in many forms of industry, including the construction of modern aircraft. COUNT 5
QSN1 Who discovered precipitation hardening alloys? ANS1 Alfred Wilm QSN2 When were precipitation hardening alloys discovered? ANS2 1906 QSN3 What happens to precipitation hardening alloys after they quenched? ANS3 harden over time QSN4 One of the first "age hardening" alloys used were called? ANS4 duralumin QSN5 What was used in the construction of modern aircraft? ANS5 duralumin