Metallurgy of Bronze Bells and Castings

H. K. D. H. Bhadeshia

Bronze used for making bells and gongs is essentially an alloy of copper and tin. Copper containing about 22-24 wt% of tin is often known as bell metal because it has a pleasing sound quality when struck.

The chemical composition results in a two-phase microstructure of α (a solid solution of tin in copper, face-centred cubic) and a β (body-centred cubic solid solution of Cu and Sn), when cooled rapidly from 600°C. Slower cooling can result in the precipitation of an embrittling δ phase of composition Cu₄₁Sn₁₁. This is illustrated in the phase diagram below.

The first set of photographs below are taken in South Korea, to illustrate the bell of King Seongdeok, now located at the Gyeongu Museum near Pohang. The bell took about 30 years to achieve. The first casting failed. The second did not give the right sound. A monk then proclaimed that a baby needed to be sacrificed to the melt. The third bell (illustrated) was made in this way. When the bell is struck, its sound at a distance is that of a baby crying for its mother. The veracity of this story is not established.

Bell of King Seongdeok, made from Bronze, Gyeongu Museum, South Korea
Bell of King Seongdeok	Bell of King Seongdeok	Bell of King Seongdeok
Bell of King Seongdeok	Bell of King Seongdeok	Bell of King Seongdeok
Liu Weijie, Harry Bhadeshia and Hae-Geon Lee

Another bronze bell, at the Bulkusa Temple (Bhuddist Country Temple), South Korea

Another bronze bell, at the Bulkusa Temple (Bhuddist Country Temple), South Korea

Another bronze bell, at the Bulkusa Temple (Bhuddist Country Temple), South Korea

The following photographs of the Bell of King Seongdeok, courtesy of Professor Hae-Geon Lee

Bronze Bell in Kaoshiung, Taiwan

At the Confucious Temple, Kaohsiung	The temple was built about 40 years ago.	At the Confucious Temple, Kaohsiung
Bronze bell at the Confucious Temple, Kaohsiung	Bronze bell at the Confucious Temple, Kaohsiung. The mark in reddish colour is where the bell in struck.	A demonstration by Professor J. R. Yang and Daniel-Ming Tsai on how the bell is struck.

Bronze Bell in Nara, Japan

Photographs courtesy of Thomas Sourmail.

Bronze Bells at the T'ongdosa Temple, Korea

The T'ongdosa Temple is one of the three famous Bhuddist temples in South Korea. Some of the remains of Buddha are located there.

Bronze bell

Bronze at the Yamadera Temple Complex, Japan

Yamadera, a Bhuddist temple. Yama stands for 'mountain' and 'dera' for temple. The sanctuary has some 40 buildings on the mountain.		Bronze bell
Bronze statue of a student of a famous poet who travelled Japan and wrote about it.	Bronze statue of the famous poet who travelled Japan and wrote about it.	Bronze at the Yamadera Bhuddist temple, Japan
Bronze at the Yamadera Bhuddist temple, Japan	Bronze at the Yamadera Bhuddist temple, Japan	Bronze at the Yamadera Bhuddist temple, Japan
Bronze at the Yamadera Bhuddist temple, Japan. This is at the summit of the mountain.	Bronze at the Yamadera Bhuddist temple, Japan.	Bronze at the Yamadera Bhuddist temple, Japan.

Bronze Casting of Picasso's Guernica

On the 26th of April 2007 it will be 70 years since the small Spanish town of Guernica was blitzed by German and Italian bombers in support of General Franco during the Spanish civil war. Picasso's painting of the same name was, according to his wishes, returned to Spain only after it became a Democracy.

These photographs are of a bronze casting of Picasso's classic, made at CENIM (Centro Nacional de Investigaciones Metalurgicas) in Madrid, as a present for Harry Bhadeshia from Carlos Garcia de Andres.

Shortly after Spain became a democracy, a small section of the army occupied parliament, but King Juan Carlos went on national television in his military attire, and ordered the army to remain in barracks. The coup attempt collapsed.

For single-handedly saving the fledgling democracy in Spain, King Juan Carlos was awarded the highest honour of Cambridge University, an honorary degree.

Bronze door in Ravello, which is a town and commune situated above the Amalfi Coast in the province of Salerno, Campania, Italy. Photograph courtesy of Professor John Knott.

Bronze bell in the railway station in Iguazu, on the border between Argentina and Brazil, within a sub-tropical forest.

Bronze birds in Johannesburg

Bronze birds in South Africa

Bronze birds in Johannesburg

Bronze Bells in Germany

Bronze bell at a museum in Dusseldorf

Bronze bell at the Max-Planck-Institut für Eisenforschung

Bronze in The Russian Federation (Moscow)

A cannon made from bronze

Near the Kremlin

• The sound of bells
• Bells in the making