I was hopping somebody might be able to help a friend of mine. She is currently completing her Masters degree in Materials Science and Engineering at Delft University of Technology, Netherlands. She has finished a literature survey, which was done on medieval iron making and the bloomery hearth furnace, which can be read (in English) here http://www.sylvialeever.web1000.com/files/Medievalironmaking.pdf.
For her graduation project, which also involves practical work, she is wanting to do a scientific analyses of 17th C harquebusier's breastplate. In particular using modern technology to not only look at the microstructure, similar to what Dr Alan Williams has done in his book the Knight and the Blast Furnace, but more importantly and, as far as we can find so far, unique, is to test its mechanical properties.
This is an area of study that most of us involved in armour production, or interested in historical armour use, really want and need to know.
So how can you help?
Below is what she needs, and who she has been in contact with so far, and an overview of her thesis proposal.
Wanted: 17th century harquebusier's breastplate (not the complete cuirass), preferably english/london made and preferably with a maker's mark. Duplex if possible, though I surmise that measuring on a monolayer breastplate will be easier.
David Starley of the Royal Armouries put me on this project, he on his turn was inspired by Anthony de Reuck, who I haven’t met yet. I have had telephone conversation and email correspondence with David Starley. I met and talked to Thom Richardson at the RA last April. I’ve also been in contact with the Dutch Armymuseum in Delft, where I visited the depot and had a conversation with curators Harm Stevens and Jan Piet Puype.
I've been in contact with some dealers, namely World Wide Arms, Michael D. Long, Garth Vincent, West street antiques, but all of them could not help me at this moment. I’m thinking now of contacting the Graz armouries, maybe they have one to spare…
Aim: to test the resistance of 17th century harquebusier’s breastplates against impacts of (lead) bullets, to look at the quality of the material used in the breastplates and to determine the mechanical properties of one original breastplate
Content of research project
- production of breastplates
- History; how and where were they produced?
- Heat treatments (is there evidence on the application)
- Mechanical treatments (cold work)
- analysis of original specimens (also based on previously done work)
- Purity / Homogeneity
- Prediction of mechanical properties
Other specific Materials Science and Engineering points of interest:
- Is there evidence for the forming of precipitates (e.g. carbides) (this is important to mechanical properties of the breastplate)
- Does the microstructure show a bainitic structure? (evidence for heat treatments)
- By looking at microstructure, determine maximum temperature reached during production
- Texture/grain orientation; can this prove an early milling process for making the sheet material?
- The diffusion of carbon during the last 350 years can also be taken into account (ca. 1mm)
Right now I’m looking at purchasing/obtaining an original 17th century harquebusier’s breastplate (without much luck at the moment).
If I can get one, the work process will be as follows:
Exterior looks; amount of corrosion, finish (rough or smooth), inconsistencies, inside vs. outside looks, shape, …
Get as much information from composition and microstructure of original as possible to order small batch of modern steel with similar composition, to make reference test plates out of. These should be tested (tensile, hardness) after various heat treatments and cold work has been performed on them. Get microstructure as close to original as possible. => determination of possible treatments that have been applied on the original.
Calculations of power/force needed to penetrate a sheet of steel of certain thickness and shape with a lead (round) bullet of certain weight. How do the mechanical properties of the steel contribute to the resistance it offers? => what kind of mechanical testing should be performed on the breastplate and how?
(Depending on how much time I have left/can spend on it): to make a (computer)model of an impact of a bullet on the shaped piece of steel. (set of parameters: angle of impact, speed of impact, weight of impact projectile, shape of impact projectile (these three parameters should be set), temperature of sheet of steel (varied between –5 and 50 degrees Celsius), …) )
From calculations and model (?) it is now possible to get a good idea of what kind of testing should be performed on the original.
Fortiter et Fortis