자료유형  

 학위논문

Control Number  

0017164305

International Standard Book Number  

9798342142700

Dewey Decimal Classification Number  

530.41

Main Entry-Personal Name  

Sinclair, Daniel.

Publication, Distribution, etc. (Imprint  

[S.l.] : Purdue University., 2024

Publication, Distribution, etc. (Imprint  

Ann Arbor : ProQuest Dissertations & Theses, 2024

Physical Description  

129 p.

General Note  

Source: Dissertations Abstracts International, Volume: 86-04, Section: B.

General Note  

Advisor: Chawla, Nikhilesh;Titus, Michael;Trumble, Kevin;Zhang, Xinghang.

Dissertation Note  

Thesis (Ph.D.)--Purdue University, 2024.

Summary, Etc.  

요약The production of aluminum components by laser powder bed fusion additive manufacturing (LPBF-AM) offers simultaneous weight reduction benefits through low material density and topology optimization. The primary limitation of the method - hot cracking in high-strength compositions - is addressed by the reactive additive manufacturing (RAM) process, which introduces ceramic-forming metallic particles to powder feedstock. In situreactions subsequently inoculate equiaxed grains, prevent cracking, and strengthen the resulting alloy. The adoption of RAM alloys in aerospace applications requires the elimination of heterogeneous defects, requiring an understanding of laser processing effects and feedstock quality. To meet these needs, the collected work presents characterization methods based on x-ray tomography, seeking to establish novel descriptors for RAM feedstock and microstructures.In the first two chapters, x-ray microscopy (XRM) is applied to produce multi-dimensional particle measurements for feedstock powder qualification. Evolving existing measure-and-classify processes, a method is described to characterize AA7050-RAM2 feedstock that is rapid, interpretable, and descriptive of the highly deformed particles observed. Applying the developed methodology to an analysis of recycled AA7050-RAM2 rationalizes decreasing particle sizes by identifying the selective removal of specific shape classes. Combined with quantitative electron microscopy of particle microstructures, sieving and heat effects are comprehensively reported, demonstrating a modernized powder analysis workflow.In the second two chapters, the characteristic reactions seen in LPBF of AA7050-RAM2 are characterized. Correlative SEM/EDS and nanoindentation identified reactive phases and their mechanical properties and found a correlation between the extent of the Al-Ti reaction and the degree of particle remelting. Using 3D XRM measurements, the populations and distributions of low- and high-reaction particles were quantified, raising questions regarding homogenization mechanisms in laser-processed, particle-reinforced alloys. Thus, thin wall samples were produced and characterized to visualize convective and thermal history effects within symmetrical tracks. Novel observed mechanisms include thermal grain coarsening, keyhole-induced convection, and pore segregation by size. The accumulated microstructural quantification and novel perspective on pore movement provide a basis to improve contouring processes in RAM alloys and to better align fluid dynamics models of printing with experimental data.

Subject Added Entry-Topical Term  

Solidification.

Subject Added Entry-Topical Term  

Fluid dynamics.

Subject Added Entry-Topical Term  

Homogenization.

Subject Added Entry-Topical Term  

Energy.

Subject Added Entry-Topical Term  

Grain size.

Subject Added Entry-Topical Term  

Cracks.

Subject Added Entry-Topical Term  

Microstructure.

Subject Added Entry-Topical Term  

Corrosion.

Subject Added Entry-Topical Term  

Raw materials.

Subject Added Entry-Topical Term  

Grain growth.

Subject Added Entry-Topical Term  

Metal fatigue.

Subject Added Entry-Topical Term  

Ductility.

Subject Added Entry-Topical Term  

Microscopy.

Subject Added Entry-Topical Term  

Aluminum alloys.

Subject Added Entry-Topical Term  

Design.

Subject Added Entry-Topical Term  

Eigenvalues.

Subject Added Entry-Topical Term  

Alloys.

Subject Added Entry-Topical Term  

Fluid mechanics.

Subject Added Entry-Topical Term  

Industrial engineering.

Subject Added Entry-Topical Term  

Materials science.

Added Entry-Corporate Name  

Purdue University.

Host Item Entry  

Dissertations Abstracts International. 86-04B.

Electronic Location and Access  

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Control Number  

joongbu:657649