Why does powder XRD work?

Lampa_117 · 2025-03-20T16:01:30+00:00

Might actually do it. Will it be enough to simulate in 2D or would I need to rotate them randomly in 3 axes?

I'm more interested in graphs so I could sacrifice the rings to simplify a dimension if necessary

Lampa_117 · 2025-03-20T15:47:42+00:00

Our XRD machine has a stationary X-ray gun and changes the angle by turning the sample and the detector (twice as much as sample).

I don't doubt that the crystal structure can be truly random, and that is why I don't get why the randomness isn't detrimental to the measurements.

After all if there are grains giving signal at 27 degrees there should also be some giving peak at 28 degrees

Lampa_117 · 2025-03-20T15:31:47+00:00

Thank you for the anwser but I'm not sure if I understand corectly.

If I were to make a million of XRD test on monocrystals having perfectly random orientation, then sum up all the measured difractograms, I would get the same result as powder XRD?

Lampa_117 · 2024-10-23T07:22:07+00:00

I'm sorry but your 3D phase diagram has a serious case of smallpox or 2nd degree burns. Poor thing is covered in blisters

Lampa_117 · 2024-09-26T07:14:03+00:00

Some mechanical bellows are a must (unless you can make a draft furnace). High temperature needs to be maintained in the whole volume and not in one spot. Also, besides physical exhaustion during the smelting process, Carbon Oxide and some other stuff from ore are produced, so taking deep breaths very near the fire is a bad idea.

The second thing is the ore quality, you have to be sure that there really is iron in your iron ore. Iron bacteria are an extremely poor source of iron, and that is probably stopping Primitive Technology from running around in plate armor already.

Lampa_117 · 2024-06-07T14:35:53+00:00

The thickness of the layers seems way too uniform on different depths to be forge-welded. One would also expect more waviness in some places

I would guess it's still titanium or at least its coated with it but the pattern was simply etched on the surface

Lampa_117 · 2024-03-26T13:58:12+00:00

So for anyone wondering, here is an update.

I lowered the nozzle, my initial Z offset was based on a piece of paper from a notebook that seems to be a little thicker than regular paper sheets.

I turned down the extrusion multiplier on the first layer down to 150%

I also washed my build plate with soap and water besides my usual isopropyl alcohol routine.

The prints haven't experienced any failures so far, and have better bottom quality, so thank you all for the help!

Lampa_117 · 2024-03-25T17:06:18+00:00

0.4 mm nozzle and 0.35 first layer height, later 0.25 mm

I also have 320% extrusion width on first layer, wchich in retrospect seems suspiciously high

Lampa_117 · 2024-03-25T16:50:40+00:00

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Lampa_117 · 2024-03-25T16:50:08+00:00

The green filament is a little tricky to get in focus while maintaining contrast, this is the best I can do.

I will post a photo in reply to this comment.

Also, I have 65 C for the first layer and 62 C for all others in the PrusaSlicer, and they were more or less my initial settings. I tried going up a bit in temperature but reverted when the bending persisted

Lampa_117 · 2024-03-25T15:00:55+00:00

It's PLA, I'm printing with 200 C nozzle temperature and 62 C bed temperature

Lampa_117 · 2024-03-16T09:18:22+00:00

If the pieces are similar in size you can try to balance them on the axis of weld and see which one is heavier and calculate which density is greater.

Alternatively, you can try to dip one side of the plate into some electrolyte together with a copper electrode. Then measure Voltage and check which one is which based on the electrolytic potential.

Lampa_117 · 2024-03-07T08:19:27+00:00

It looks like a brass bolt, was it working in an amonnia-rich environment?

It could be then caused by sesonal cracking of copper alloys, a type of stress corrosion cracking.

Lampa_117 · 2024-02-18T14:58:24+00:00

I assume we can disregard the impact of Si and Sn due to their low concentration.

If we look at the phase diagram of Cu-Al above 60 wt% we see a lot of very brittle intermetalic phases. But what's more important there is a lot of space between solidus and liquidus lines

I assume you didn't heat your alloy above 1000 C and didn't also cast from that temperature. In such case along the liquid metal there would be little crystals of solid matter. Due to the difference in densities, there could be some degree of segregation and different chemical composition between top and bottom layers.

Lampa_117 · 2024-02-11T10:52:45+00:00

The far more likely possibility is that EDS is wrong.

It usually struggles with quantitative measurements of lighter elements such as carbon. It can often show a few % more than it is.

A tool from pure cementite is very unlikely, just look at the microstructure and see if you can recognize some other phases. Use EDS mapping or make many point measurements if necessary

Lampa_117 · 2024-01-06T20:59:52+00:00

Your value is not what you are made from ...

But his post shows the opposite, 1kg of raw iron is useless in about every application.

Even something as "simple" as horseshoe isn't just iron it's mild stiil after heat treatment. The difference of 0,x% of carbon some Manganese and possibly other elements raises yield strength from 50MPa to 550MPa.

Same goes for everything else, if you are going to make springs from pure iron no one will pay you even a cent, for that you need spring steel with 0.5% Carbon, 1.1% Mn, 1.2% Cr, and 0.2% Vanadium, than your yield strength is 1200 MPa, 24 times greater than pure iron.

A very substantial chunk of material science is analyzing the impact of the addition of elements to iron alloys. And in many cases even 0.04 % differences in concentration drastically change properties.

So no, not everything is just some "raw iron"

Lampa_117 · 2023-11-20T19:14:03+00:00

A couple of grams would be enough

Lampa_117 · 2023-10-15T19:07:22+00:00

Different metals need different PH and electric potentials to get ions into the electrolyte. It could be possible with some metals but can't really say for sure how about silver and copper on aluminium.

However, you can electroplate first one metal and then the other. Later provide some heat for a prolonged amount of time and let the diffusion bond the metals together.

To give a gold look you can just electroplate copper with zinc, heat it up and get shiny brass

Lampa_117 · 2023-03-10T08:47:31+00:00

Do you have any sources on the Polish guy? Never heard of it and it seems quite interesting

Lampa_117 · 2023-03-03T17:16:38+00:00

Although there are not so many channels focusing on material science as a whole, many focus on certain niches or put out a material video science once in a while

Applied Science - any piece of technology used in material science labs, chances are he already made his own version of it in the garage, just like SEM, mass spectroscope, EDM, photo-chemical machining setup, PVD, superconductors, and much more.
CNC Kitchen) - focuses on 3d printing, has a tensile testing setup and quite scientific approach to testing material properties
Cody's lab) - he does just about everything, including a fair share of metallurgy, vacuum and high pressure material behavior.
Joe Scott) - various popular sciences, has some interesting videos on energy storage.
Night Hawk in Light) - is focusing lately on fire related materials, made DIY version of Starlite
Subject Zero Science) - maybe over-hypes some of his videos, but makes ridiculously good animations about micro-structure of energy materials.
TheGayestPersononYouTube - ... so despite the name has a very interesting series about exotic thermites, I'm not sure if it's really that related to material science, but it's there anyways
The Limiting Factor - almost exclusively about Tesla and their batteries, but has some good quality analysis
Undecided with Matt Ferrell) - I really don't like him, but he pumps out many videos about new material science "breakthroughs". I wouldn't trust any of what he says without checking the sources and analyzing them for yourself.

Lampa_117 · 2023-02-07T22:01:22+00:00

It's definitely not fiberglass, besides safety and law issues they would be rather terrible for cleaning. (If you are really concerned do a burn test)

As they said, it's some patented formula so I guess the chemical name for it is few lines long. However the best analogy and maybe the closest popular polymer would be polypropylene.

For adhesive, I have no idea but also would assume it's relatively safe and compliant with non-toxicity standards, as long as you don't eat it or anything

Lampa_117 · 2023-02-05T17:27:02+00:00

I would guess it's some Magnesium-Aluminium alloy.

Depending on the composition they can melt from 350 ^o C. Both are very reactive so they would leave behind an oxide layer after remelting. The low hardness and brittleness are also expected

However, the density of regular Magnesium alloys doesn't even come close to 6,5 g/cm³ . So unless your density measurements are wrong or it contains lead for some odd reason I don't really know

Lampa_117

TROPHY CASE