This is concerning.
As portions of the auto industry experiments with alternative fuels and lightweighting, some unknown problems inevitably will be encountered. One we hadn’t even considered before is cause for concern with hydrogen interacting with a certain material, potentially causing structural failures. This clearly illustrates the need to thoroughly vet emerging technologies instead of blindly rushing into adoption.
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This problem is high-strength steel, which is becoming more common in car structures, suffering from hydrogen embrittlement. Researchers at Sophia University in Japan, where hydrogen fuel cell vehicles are becoming more common, have done experiments on fractures in high-strength steel to better understand the phenomena so they and others can devise ways to guard against it.
Obviously, having any structural component in a vehicle break down and lose integrity is bad. It can cause a failure of critical features in a crash, turning what should have been survivable into a fatal situation, as well as many other potential problems.
When hydrogen atoms diffuse into the structure of high-strength steel, it begins weakening the material, something called embrittlement. In this study, researchers created a new way to conduct tensile tests on high-strength steel, allowing them to produce only intergranular fractures.
While hydrogen fuel can cause embrittlement in high-strength steel, it can even be triggered by the hydrogen in water from rain, a car wash, or other sources. Having such a common element cause a vehicle to lose structural integrity is less than optimal.
High-strength steel has become increasingly popular in modern cars as automakers seek ways to cut curb weights. You might already be aware just how much bigger and heavier today’s cars are versus those made in the 80s, putting a strain on fuel efficiency and even posing safety hazards. With high-strength steel, the weight-to-strength ratio is high, allowing engineers to create designs with less metal without sacrificing structural integrity.
Images via Toyota, Chevrolet, Sophia University