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Materials Engineering

Research / Solder Research / Staff

Welcome to the solder research webpages



Professor Bill Plumbridge

Colin Gagg

Dr. Jim Moffatt

Dr. Martin Rist

Dr. Ray Matela

Gordon Imlach

Peter Ledgard

Yoshi Kariya (left 2001)

Shellene Cooper (nee Peters) left 2002

Jon Jones

Ayumi Mori (left 2001)

Angus Westwater

Xian Wei Liu (left 2006)

Bill Plumbridge

Professor Bill Plumbridge has spent over twenty five years researching into the high temperature mechanical behaviour of engineering materials. These have included low alloy and stainless steels for conventional and nuclear power generation; nickel and titanium alloys for gas turbines, and ceramics. He aims to transfer the technology of those areas to the interconnection problem. He established the solder programme at the Open University in 1992.

Colin Gagg

Colin Gagg's research interests are in creep, creep rupture and monotonic characteristics of lead and lead-free solder systems. Has an active input into the development of a sound materials properties database against which candidate replacement alloys may be compared. A principal aim is to ensure that stress analysis and modelling for life prediction employ appropriate and reliable data. He has pioneered creep testing at sub zero temperatures.

Jim Moffatt focuses upon the high strain fatigue behaviour of solder alloys. This includes continuous cycling and cycles containing dwell, periods which lead to fatigue-creep interactions. Examination of failed and partially failed specimens enables the nature and development of damage to be monitored

Dr. Martin Rist is researching creep of lead free solder alloys. This new breed of environmentally-friendly solder alloys contain high proportions of tin, typically over 90%. The key microstructural feature in the tin-based alloys is the presence of small intermetallic phase-particles, attempts are currently being made to incorporate  the associated matrix-particle effect into creep analyses using the concept of internal stress.

Dr Ray Matela has established expertise in finite element analysis and modellling. He is involved in modelling and predicting the behaviour of simple joint geometries, employing the data generated by the testing programmes.

Xian Wei Liu , a post-doctoral researcher, is studying the behaviour of model solder joints, particularly during thermal cycling. He intends to compare his data with that for bulk solders and with actual board performance. Emphasis will be placed on life prediction and microstructural changes produced by thermal cycling.

Gordon Imlach is responsible for the analysis of raw materials prior to casting. Samples of all alloys are examined by differential scanning calorimetry (DSC) and those with even minor impurities are rejected.

Peter Ledgard is involved in the design and manufacture of ancillary equipment used in the programme. This includes test chambers, specimen moulds and modifications to any item of equipment, such as the creep frames.


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