Development of a Near Net Shape Processing Method for Rhenium Using Directed Light Fabrication

1998 ◽  
Vol 13 (5) ◽  
pp. 719-730 ◽  
Author(s):  
John O. Milewski ◽  
Dan J. Thoma ◽  
Joe C. Fonseca ◽  
Gary K. Lewis
2012 ◽  
Vol 715-716 ◽  
pp. 794-799 ◽  
Author(s):  
Cheng Liang Miao ◽  
Cheng Jia Shang ◽  
Guo Dong Zhang ◽  
Guo Hui Zhu ◽  
Hatem S. Zurob ◽  
...  

Stress relaxation was studied in a series of low carbon, high Mn microalloyed steels containing 0.012, 0.06 and 0.1 wt% Nb. The stress-relaxation curves were modeled using a physically-based model that takes into account the time evolution of precipitation, recovery and recrystallization as well as their interactions. The results confirm that high Mn-high Nb design can offer distinct advantage over the low-Mn design for the application of near net shape processing.


2012 ◽  
Vol 77 ◽  
pp. 190-195 ◽  
Author(s):  
Kalan Bastos Violin ◽  
Tamiye Simone Goia ◽  
José Carlos Bressiani ◽  
Ana Helena de Almeida Bressiani

Titanium and its alloys are widely used as biomaterials and interact well with bone tissue. In order, to evaluate more than just morphological osseointegration by histological slides the work aimed to approach a molecular evaluation of bone-implant using lectinhistochemistry (LHC), which binds with high specificity carbohydrates (sugar residues) presents in membrane glycoproteins with the use of lectins. The implanted samples were obtained by powder metallurgy, Ti-13Nb-13Zr alloy with and without gelatin. Pores were achieved by adding gellatin 5 wt% to the hydrogenated metallic powder, after near net shape processing, the samples were thermal treated in vacuum (300 °C/90min) and sintered in high-vacuum (1150 °C/14h). The samples were characterized for porosity (~30%), and subsequently were implanted in rat’s femur bone. After 4 weeks of healing process, bone with implant were sampled to perform LHC in paraffin embedded tissue in histological slides using the lectins PNA, UEA-1, WGA, sWGA and RCA-1. All samples osseointegrated well with the bone, no fibrous capsule was present in the bone which was in contact with the implant. With the molecular approach of osseointegration, adjustments in the processing and structure of macroporous titanium based implants can be performed to achieve friendly structure.


2013 ◽  
Vol 473 ◽  
pp. 35-38 ◽  
Author(s):  
Xia Zhu ◽  
Keiji Ogi ◽  
Manabu Takahashi ◽  
Nagatoshi Okabe ◽  
Kazuki Mori

This paper proposes a new near-net-shape working method to partially enlarge and control shaft's cross section through a metal mold. This study investigates the changes in the sectional area of shafts during the processing under various processing conditions, and evaluates the changes with a filling ratio. We introduce the processing method and the processing conditions, and then we report the results of processing experiments. Lastly, we clarify that processing conditions influence on the geometry of the processed part.


2014 ◽  
Vol 1019 ◽  
pp. 3-10 ◽  
Author(s):  
Brian Gabbitas ◽  
Fei Yang ◽  
Stella Raynova ◽  
Ming Tu Jia

Both open die and closed die powder compact forging can be used for the consolidation of Ti and pre-alloyed Ti 6Al 4V powders produced by a hydride-dehydride (HDH) process. The approach used is initial cold or warm compaction into cylindrical shapes, or into a specific pre-form shape appropriate for achieving a particular final forged shape. The economic benefit is near net-shape processing with minimum machining required after forging. Manufacturing costs are also minimised by forging a compact, with a sufficiently high enough density, in air, without a protective atmosphere. The challenge, from a manufacturing point of view, is the operation of a manufacturing route which gives rapid and qualified compaction to meet production demands and batch sintering to achieve a high enough density prior to final forging to shape. In addition to this the final product has to have the right level of mechanical properties. This paper reviews some key findings from powder compact production, through to sintering and forging. These will be presented in terms of alpha-beta phase distribution in the microstructure, the degree of porosity, heat treatment and their effects on mechanical properties.


JOM ◽  
1987 ◽  
Vol 39 (5) ◽  
pp. 26-27 ◽  
Author(s):  
Steven G. Fishman

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