Constance Fligg Elam was born in New Barnet, Hertfordshire, the daughter of surgeon William Henry Elam, and Lydia Coombes. She was educated at Saint Felix School, Southwold before studying Engineering at Newnham College, Cambridge. Tipper achieved a third class in Part I of the Natural Science Tripos. In 1915 she joined the Metallurgical Department of the National Physical Laboratory in Teddington, but moved in 1916 to the Royal School of Mines, where in 1917 she was appointed Research Assistant to Sir Harold Carpenter and, in 1921, elected to the Frecheville Research Fellowship. Also in 1917 she was elected a member of the Institute of Materials. It was subsequently arranged that she should work at the Cavendish Laboratory, Cambridge. In 1924 she was appointed to the first Research Fellowship in Metallurgy given by the Worshipful Company of Armourers and Braziers. In 1928, Elam married George Tipper, a graduate of Clare College, Cambridge, and the Superintendent of the Geological Survey in India. When she left the Royal School of Mines in 1929, with a DSc, she settled in Cambridge and continued her work there for over 30 years. Tipper was appointed as a lecturer in the Department of Engineering from 1939, as one of the first women lecturers in the university at a time when many male lecturers went off to wartime work. In 1949 Tipper was appointed as a Reader at Cambridge University, becoming the only full-time woman member of the Faculty of Engineering. She remained at Cambridge until her retirement in 1960. Following her retirement, Tipper continued to work as a consultant in the North-West of England, advising on metallurgy in submarine construction. Her 100th birthday in 1994 was celebrated by Newnham College with the planting of the Tipper Tree, a sweet chestnut.
Research
Tipper specialised in the investigation of metal strength and its effect on engineering problems. Her research with G. I. Taylor on distortion of aluminium crystals under tension received the 1923 Royal Society Bakerian Medal, although Tipper was prevented from attending the celebratory dinner due to being a woman. This research later inspired Taylor's explanation of plastic deformation by dislocations. During World War II she investigated the causes of brittle fracture in Liberty Ships. These ships were built in the US between 1941 and 1945, and were the first all-welded pre-fabricatedcargo ships. Tipper established that the fractures were not caused by welding, but were due to the properties of the steel itself. She demonstrated that there is a critical temperature below which the fracture mode in steel changes from ductile to brittle. Because ships in the North Atlantic were subjected to low temperatures, they were susceptible to brittle failure. While these fatigue cracks would not propagate beyond the edges of riveted steel plates, they were able to spread across the welded joints in the Liberty ships. She developed what is now known as the "Tipper Test" to help ensure that the metal used in ship construction was sufficiently sound. She was the first person to use a scanning electron microscope to examine metallic fracture faces. She used a scanning electron microscope built by Charles Oatley and his team, the second SEM ever built. Dr Tipper was awarded the Thomas Lowe Gray Prize, jointly with Professor J F Baker, for their paper 'The Value of the Notch Tensile Test', read before the Institution of Mechanical Engineers in October 1955. The International Congress on Fracture awards the Constance Tipper Silver Medal to mid-career scientists and engineers who have made significant contributions in any aspect of research in the field of fracture.
