How can you get copper into your alloy?
- Thread starter 3856imp
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pokute
Active Member
Basically, what it says is that sometimes enhancement of the grain boundary results in a 2 phase alloy where the grain boundaries act like the fill in a composite. Like fiberglass. Evidently copper can be used to create this condition in bullet metal. To do this in a controllable way, the Cu should be precipitated by reduction from a salt, as several people here are doing with Copper Sulfate.
fiver
Well-Known Member
right but it also shows it working both way's depending on what it is paired with and what they are suspended in.
we already have a crystal that breaks down allowing the lead to move and flow, but we also have the copper in there being a boundary metal.
this doesn't allow or promote the fracturing, it contains much of it and merely distorts.
this still lets the main alloy flow but without the boundary fracturing.
that's where the strength and malleability comes from.
that is a good read even though it doesn't pertain exactly to lead type allows.
we already have a crystal that breaks down allowing the lead to move and flow, but we also have the copper in there being a boundary metal.
this doesn't allow or promote the fracturing, it contains much of it and merely distorts.
this still lets the main alloy flow but without the boundary fracturing.
that's where the strength and malleability comes from.
that is a good read even though it doesn't pertain exactly to lead type allows.
pokute
Active Member
The copper isn't really creating a boundary by itself, it's creating a relatively wide zone of what's called "dislocation pileup", where the main metal, in our case lead, cannot grow large crystals because the large copper atoms get in the way, and instead grows a tangle of small crystals in a net of "defects". The defect net is the actual reinforcement that, in this special case, increases the toughness of the bulk alloy.
main alloy flow but without the boundary fracturing That is IMHO the secret. The Cu should be bound up with Sb/Sn(if present). Oxidation of the Cu doesn't happen in boolits as no oxygen there - unless the Sb or Sn oxides release the O. I posted a pic sometime of a 40sw TC I shot into a rock pile. TC nose was sheared down the middle to 2 different lengths but no fracture line at the intersection. It also looked more like a WC and >98% wt retention. Handling did get a few powder sized grains flaking off.
M3845708Bama
Active Member
6x45 with 105 grn. Pced at a little above jacketed velocities and 308 W with 160 actually 168 with GC and PCed. Bullets were loaded to jacketed by book (Lymans) but from 150 to 350 fps higher than book through crono, guess PC is that slick afterall. No pressure indications were noted but at highest velocities accuracy deteriorated rapidly.
Kevin Stenberg
Well-Known Member
I just went to the lead alloy calculator. They list copper content as 1.5 % of Pewter
waco
Springfield, Oregon
...Choked frogs teeth......
pokute
Active Member
That was Babbitt. This is Pewter. Not to mention Ormolu, German Silver, and Pot Metal.
pokute
Active Member
You mean my aunt Lil? She was a cocktail waitress. High silver content. Mostly 50 cent pieces. Walking Liberty's and Franklins.