A post split in two, dedicated to different audiences (with a possible overlap):
- Metallic Parts Designers open to considering Additive Manufacturing;
- Fatigue Resistance Geeks.
If you fall into either category—or both—you’ll want to read on.
1. AM, Scalmalloy® and Fatigue Resistance.
If you’re a Components Designer and consider Additive Manufacturing with Scalmalloy® powders, we recommend you reading this work: it gives a significant contribute to the understanding of Scalmalloy® fatigue resistance – a debated topic.
The effect of orientation is described, as well as the benefit from smoother surfaces obtained by treatments like sandblasting (surface roughness can act as stress concentrator).
Predictive models are applied, including the R-curve method, which accounts for crack growth resistance and provides improved predictions, especially in scenarios involving small defects or short cracks.
2. Only for Fatigue geeks (we told you)
Let’s bring the clock back to September 2003: the 1st International Conference on Fatigue Crack Paths (FCP2003) is held in Parma, Italy.
Renown and revered Professor Yukitaka Murakami, from Kyushu University, attends the event.
During social interactions, he keeps praising the experience he had with an Italian graduate who ran his PhD in his team a few years before:
Very skilled young man, with great spirit for the work environment of his department.
If you’re not a geek but ignored our warning, you need to know that Professor Murakami contributed to the study of Fatigue resistance of metals in connection to microstructure, small defects and short cracks propagation. He identified the possibility of variations in the resistance to crack propagation, in line with the Cyclic R-curve theory.
All of that was initially applied to wrought metals. That very conference (or the following 15th European Conference on Fracture (ECF15), held in Stockholm in August 2004) marked the beginning of his activity in Powder Metallurgy:
First pressed and sintered Iron mixes; more recently, additive manufacturing Titanium and Nickel alloys. What happened is that a young fella he tried to recruit in Parma politely declined, but invited him to look into fatigue resistance of PM parts.
Now, why do we even dare mentioning Professor Murakami’s name?
Let’s tie the story together:
That talented and well spirited PhD student was Stefano Beretta, now professor at Politecnico di Milano and visiting professor at National Center for Additive Manufacturing Excellence (NCAME) in Auburn University.
We heard great things about him from the NCAME team, during the recent MILAM show in Tampa FL.
Prof. Beretta coordinated this publication and you can see professor Murakami’s works cited in the Literature references. Naturally.
We therefore congratulate author Daniel Perghem and co-authors Lorenzo Rusnati, luca patriarca, Federico Uriati for their work, on the footsteps of two Fatigue Studies legends.