DESIGN OF THE SUSTAINABLE METALLIC MATERIALS:

NEW OPPORTUNITIES IN RESEARCH AND MATERIAL SCIENCE EDUCATION

D. Yan, M. Wang, L. Morsdorf, M. Koyama, C.C. Tasan

ODTÜ Metalurji ve Malzeme Mühendisliği Bölümü

50. Yıl Sempozyumu – 29.06.2016

Background

• Materials innovations are key in all technological advances...

Background-ii

• Multi-phase systems enable innovative property combinations…

FEI Company, R. Swadźba

γ’

γ

Background-ii

• Multi-phase systems enable innovative property combinations…

Song et al., MST, 2000

Background-ii

• Multi-phase systems enable innovative property combinations…

Martensite

Austenite

Background-ii

• Multi-phase systems enable innovative property combinations…

Background-iii

• Yet, multi-phase systems have several active damage mechanisms…

γ’

γ

Martensite

Austenite

Challenge

Solution

[White et al., Nature 2001] [www.selfhealingconcrete.de/] [Zhang et al., JAC, 2014] [Demkovitz PRL, 2014]

polymers ceramics fewer examples for metals!

Self-healing Polymers, Ceramics, Metals

Self-healing metals: typically exotic systems!

Grabowski and Tasan, Adv. Polym, Sci. (2016)

self-healing: “autonomic closure of micro-cracks”

• critisms

– proposed mechanisms not generic (hence no real ecological solution)

– not all closed cracks are healed (probably closed crack remains weakest spot)

– not all cracks are critical (most parts have up to 1vol.% damage upon forming)

– performance benefits questionable (why not just pick a better alloy?)

• what would be ideal?

– generic approach

– ‘healing’ all critical damage incidents

– with clear performance benefits

• self-healing: “autonomic closure of micro-cracks”

• healing: “non-autonomic retrieval of crack-arresting ability”

Solution-ii

healing

What is needed?

(a) Guidelines for damage-resistance

(b) Guidelines for healability

In-situ testing

Toolbox: Multi-field mapping

phase A

phase B

strain

damage

stress

topography

stress

strain

damage

X’graphy

Tasan et al., Acta, 2014

Tasan et al., IJP, 2014

Yan et al., Acta, 2015

Toolbox: Multi-field mapping

Hydrogen trapping & embrittlement

Koyama et al., Acta, 2014 Hu et al., in review

Graded dual phase steel design

Yan et al., in review.

Design of ductile martensitic steels

Saq: As-quenched S1h: 600°C 1h

γ%: 10%

S8h: 600°C 8h

γ%:37%

Wang et al., Acta Mat (2014)

Wang et al., Acta Mat (2015)

Novel, metastable, High entropy alloys

Fe20Mn20Ni20Co20Cr20 Fe50Mn30Co10Cr10

Li, Pradeep, Deng, Raabe, Tasan, Nature (2016)

What is needed?

(a) Guidelines for damage-resistance

(b) Guidelines for healability

Strategy for Healability

Tasan et al. Scripta Materialia (2010)

Zhang et al., Mater Char, 2016

Morsdorf et al., Acta, 2015

Strategy for Healability-ii

Conclusions

• Innovations in structural materials are still desperately needed.

• Yet, environmental concerns are serious, and they require action.

• We develop and employ multi-field mapping tools…

• … in order to design damage-resistant & healable alloys

• Several new opportunities & challenges: exciting times ahead!

Sevgi ve saygiyla…