Alloy are relatively similar in size, the atom exchange method usually happens, where some of the atoms composing the metallic crystals are substituted with atoms of the other constituent. This is called a "substitutional alloy". Examples of substitutional alloys include bronze and brass, in which some of the copper atoms are substituted with either tin or zinc atoms respectively. In the case of the interstitial mechanism, one atom is usually much smaller than the other and can not successfully substitute for the other type of atom in the crystals of the base metal. Instead, the smaller atoms become trapped in the
Sundown Tin and Copper Mine 28 July 2000 having satisfied the following criteria. The place is important in demonstrating the evolution or pattern of Queensland's history. The Sundown Mine is of historical importance because of its combination of tin, copper and arsenic production, the primary product at any given time varying with the prevailing market condition. Thus at one site is a microcosm of the forces influencing the pattern of most mining in this region of southern Queensland. The Sundown Mine together with the Beecroft Mine and the Jibbenbar State Arsenic Works, is associated with the prickly pear eradication program. The place demonstrates rare, uncommon