My kid explained how the failure of the Titanic, WWII Liberty Ships, and Hinkley Nuclear Reactor...

[NNadir]

...are all related.

Actually, he didn't explain the Hinkley reactor failure, an explosion in the team turbine (the non-nuclear portion) in 1969; I came across that while looking into what he told me.

He's getting his Ph.D. in nuclear materials and is trying to design alloys that are combinatorically optimized for exhibiting the following properties: Strength, fracture resistance, radiation resistance, low neutron capture cross sections, corrosion resistance, machinability and weldability and even printability.

It is, as one can see, a rather tall order, a worthy exercise and challenge.

I'd reached out to him because I was contacting a scientist to give a presentation at some events I'm putting together, and the scientist question was within his scientific degrees of separation and wanted to be sure my son was comfortable if I mentioned his name in this context. (I'm trying to be overly polite and considerate, at least in my family.)

Anyway, we ended up discussing oxygen in steels, and I made some suggestions for him to think about by meandering a bit around the periodic table and discussing oxides of various elements and their properties - making one serious mistake about which I'll inform him. During our conversation, he went off on a riff of why oxide dispersion is important, remarking off hand that this is why the Titanic and the Liberty Ships during World War II failed.

The issue is temperature embrittlement.

In the case of Hinkley and the Titanic it is described in this paper:

H.J. Kong, C. Xu, C.C. Bu, C. Da, J.H. Luan, Z.B. Jiao, G. Chen, C.T. Liu, Hardening mechanisms and impact toughening of a high-strength steel containing low Ni and Cu additions, Acta Materialia, Volume 172, 2019, Pages 150-160.

A relevant excerpt from the article:

Despite the successful development of 1000 MPa grade ferritic HSLA steel strengthened with a high number density of ultra-fine Cu-rich precipitates through minimal Ni additions, the steel requires a peak aging at 550 °C [8] that falls within the 300–600 °C temper-embrittlement regime. The 300–600 °C temper-embrittlement still remains an unsolved issue [1,10] in HSLA steels, limiting their widespread in various engineering applications, especially in turbine rotors applications. Temper-embrittlement is a problem not only for the HSLA steels but for all ferritic and martensitic steels. The sinking of the Titanic and the burst of a nuclear power plant in Hinkley point in 1969 [11] are the two well-known metallurgical catastrophes due to temper-embrittlement that are worth contemplating. The temper-embrittlement is also known as reversible or double-step embrittlement. It is characterized by the loss of impact toughness, right shift of ductile-to-brittle transition temperature (DBTT), and brittle intergranular impact fracture along prior austenite grain boundaries. The fracture path corresponds well to the segregation of tramp elements such as phosphorus (P), antimony (Sb), tin (Sn), sulphur (S), and arsenic (As) [12] at the prior austenite grain boundaries after tempering between 300 and 600 °C or at even higher temperatures followed by slow cooling [13]. The embrittlement is even worse in the presence of Cu, Cr, Ni, and Mn [[14], [15], [16]].

I added the bold.

A second paper is even more interesting, as it concerns not only the titanic but the high failure rate of "Liberty Ships" which despite their failure rate were important in helping the US to be on the winning side in World War II.

That paper is this one:

Branislav Djordjevic, Aleksandar Sedmak, Blagoj Petrovski, Aleksandar Dimic, Probability distribution on cleavage fracture in function of Jc for reactor ferritic steel in transition temperature region, Engineering Failure Analysis, Volume 125, 2021, 105392.

The fun text on the history of this problem:

1. Introduction – history of failure in transition region and case studies
One of the first low temperature fracture problems which involved the academic community, was the failure of Liberty ships. Out of 4964 ships of this type, made by welding during and before the Second World War, 233 literally broke in half, whereas 1289 had suffered severe damage. These fractures were brittle with very little or no plastic strain. Initially, it was believed that the cause of failure was the increased brittleness of welded joints compared to riveted structures, or that it was caused by quenching of material near the necks [1]. However, it was determined that, in addition to welding effects and residual stresses, the real cause was the toughness transition temperature of sheets from which the ships were made. While the sheets of ships that were destroyed had shown transition temperature between 15 and 70 °C, for sheets of non-damaged ships, this temperature ranged from 15 to 55 °C [2], [3], [4]. Due to this, the chemical composition of the used steel sheets have been changed. For example, the carbon content has been reduced and the manganese content has been increased, which led to the decreasing of transition temperatures as well as transition region lowering between −25 °C and 25 °C. This research then influenced studies about the sinking of the Titanic and other ships from that era.

During exploitation, pressure equipment are subjected to various working and environmental conditions, including work pressure and temperature, corrosion, etc., which could lead to brittle fracture. One of the first major disasters related to pressure vessels took place in 1919. Just 4 years after it was built in the Boston, a giant storage tank exploded, releasing a flood of molasses. After appropriate investigation, factors that lead to this catastrofic accident are: poor fabrication practices, low material toughness, and design practices contributed to the failures [5], [6]. In this period, the term transition temperature was still not known, since studies of this problem started with Liberty ships failures. Another catastrofic event was happened in South Africa 1973. A pressurized ammonia bullet-type tank that was operated near ambient conditions had required weld repairs near a dished head seam. The tank had not been stress relieved at the time of manufacture, nor after the weld repairs. Later material testing also indicated poor toughness properties with the transition temperature above ambient conditions [5]. During sevice, an ammonia leak developed in the dished head, which apparently chilled the area so that a 4-foot portion of the dished head failed “in an explosive manner” [5], [7]. A series of studies followed, for the purpose of determining and undertanding why certain disasters happened, so that they could be avoided in the future. Studies by Filipović [8], [9] can be used as examples, in which the analysis of failure of two pressure vessels revealed that it was caused by environmental conditions. The fracture mechanisms of both vessel was quite different, brittle in the first one, and completely ductile in the second, although the base metal (which was ferritic) of both vessel that they were made off was of the same thickness and sufficient specified ductility. For first case it is supposed that during the proof pressure test, the underground storage tank had been exposed to the temperature lower than the nill ductility transition temperature, and the initiation of the britlle crack in plane strain situation can be attributed to this testing condition.

So we can add molasses and ammonia to the Hinkley Nuclear Reactor, Liberty Ships, and the Titanic.

Over in the wilderness industrial development forum here, whoops I mean the E&E forum, we have a set of fossil fuel sales people and salesbots rebranding fossil fuels - at a tremendous cost in exergy destruction - as "hydrogen," and misrepresenting hydrogen as "green," whereas it is a very dirty fuel.

A Giant Climate Lie: When they're selling hydrogen, what they're really selling is fossil fuels.

The materials science issues in hydrogen storage, particularly at the extreme cryogenic temperatures involved, extreme pressures, and chemical incompatibility - hydrogen embrittlement is well known - make all of the above seem like child's play not that these realities are likely to disturb the dangerous fantasies being sold.

Just saying...

Anyway, yesterday I was a pretty happy father, having been schooled by my kid. We had a nice conversation and he showed some respect for his old man's ideas and even some philosophy of experimentation. I had pushed him to cover other areas of research, given my selfish investment in living vicariously through him, but he's chosen his own path in concert with his advisor, and frankly, it's a damned good one with real challenges.

I'm a happy Poppa.

[Jaydog]

1. I thought it hit an iceberg.

[NNadir]

2. Yes, but the question is why the iceberg broke the steel.

Were the steel not embrittled, the collision with the iceberg probably would have resulted in a big dent which would be forgotten by now.

[Jaydog]

3. Just joking

Very interesting info.

[VMA131Marine]

8. That's debatable

The Titanic’s hill was riveted construction not welded. What’s been observed in the wreckage is that the rivets failed not the hull plates opening up the ship to the sea. It’s also not appreciated how small the total area of the openings were: only 12 to 13 square feet or about one square meter. It was enough to sink the ship, but only just because the first six compartments were penetrated and the sixth one only barely. Many of the rivets recovered from Titanic’s wreck have been found to have imperfections and slag inclusions that reduce their strength significantly. Further the steel became brittle in the cold temperatures.

All that said, RMS Olympic, Titanic’s older sister was built in the same yard under the same conditions, and with the same materials and she was in service until 1934 without experiencing any structural failures. She just became obsolete.

[NNadir]

9. The statement "the steel became brittle in the cold temperatures" is the issue described in the...

...papers.

The rivets are also steel, and rivets do fracture.

The brittleness may not have had much importance without an iceberg collision, although it was very much an issue in the Liberty Ships.

My son told me, without reference, that no one actually believed that it was an issue until a Liberty Ship broke apart in New York Harbor on a very cold day.

[cachukis]

4. Cool.

[dchill]

5. So, it's about the mettle of the metal!

[NNadir]

6. Indeed, and I'm trying not to meddle in the metal mettle metallurgical metal metrology.

It's my son's show.

[dchill]

7. And congratulations to you both!

[Chainfire]

10. I thought the Titanic sank because of a massive excess of hubris.

That and the karmic results of calling a ship "unsinkable."