Development of third generation advanced high strength steels

<p>"Lightweight duplex steels with combinations of either bainite, acicular ferrite, and austenite or martensite and austenite were investigated as third generation advanced high strength steels targeted for automotive applications. Large additions of manganese (>13 wt%) and carbon (</p> <p>Duplex steels with different volume fractions of primary <em>δ</em> -ferrite were used to study the crystallography of austenite formed during the peritectic reaction. Solute profiles across the peritectic interface showed aluminum segregated near the interface which promoted bainitic ferrite formation. Thermal treatments were used to manipulate the concentration and type of oxides and the ferrite plate density was found to correlate with inclusions of low misfit in steels with austenite grain size of 16.5 µm.</p> <p>A steel with bainite and acicular ferrite produced an ultimate tensile strength of 970 MPa and elongation of 40%. The mechanical properties depended on the strengths and size of the microstructural constituents. Work hardening behavior was examined in a steel exhibiting multiple martensitic transformation induced plasticity (γ -austenite→(ε-martensite->α-martensite). A strain hardening exponent as high as 1.4 was observed with ultimate tensile strength and elongation as high as 1,165 MPa and 34%"--Abstract, page iv.</p>

Name thesis:degree_name

Ph. D. in Metallurgical Engineering

Grantor

Missouri University of Science and Technology

Year dc:date.available

2016

Author dc:creator

• McGrath, Meghan C.

• Metallurgy

Repository record dc:identifier

https://scholarsmine.mst.edu/doctoral_dissertations/22

OAI identifier oai:identifier

oai:scholarsmine.mst.edu:doctoral_dissertations-1024