Why are they called brass instruments?
Brass instrument
The view of most scholars (see organology) is that the term "brass instrument" should be defined by the way the sound is made, as above, and not by whether the instrument is actually made of brass. Thus one finds brass instruments made of wood, like the alphorn, the cornett, the serpent and the didgeridoo, while some woodwind instruments are made of brass, like the saxophone.
Cymbal alloys
Bell bronze, also known as "bell metal", is the traditional alloy used for fine cymbals, many gongs, and, as the name suggests, bells.
It is normally stated to be one part tin to four parts copper, that is 20% tin, and this is still the most common formula, but there has always been some variation. Larger and smaller bells are cast with differing amounts of tin, and some bell, gong, and cymbal makers use small but significant amounts of other elements, notably silver, gold, and phosphorus.
Bell bronze is a two-phase alloy, meaning some of the tin is not dissolved in the copper grains but exists between them. This makes the metal harder and more brittle than a single-phase alloy,
and also affects the way the metal responds to hardening by hammering and lathing, and greatly restricts the use of mechanised techniques of manufacture. Major orchestras generally use bell-bronze cymbals, which are capable of a greater dynamic range than any others. They are also generally the preferred cymbals of drum kit players.