STATISTICAL ANALYSIS OF THE EARLY STAGES OF PHASE DECOMPOSITION BY ATOM PROBE

1988 ◽  
Vol 49 (C6) ◽  
pp. C6-427-C6-432
Author(s):  
M. G. HETHERINGTON ◽  
M. K. MILLER
2016 ◽  
Vol 877 ◽  
pp. 231-236 ◽  
Author(s):  
Olaf Engler ◽  
C. Schäfer ◽  
Henk Jan Brinkman ◽  
Calin D. Marioara ◽  
Masaya Kozuka ◽  
...  

In this study we aim at combining the results from transmission electron microscopy (TEM) and atom probe tomography (APT) to study the early stages of phase decomposition in the age hardening alloy AA 6016. Samples are subjected to different periods of natural ageing or artificial pre-ageing at elevated temperature in order to produce different types of clusters and early stages of precipitation before age hardening commences. APT is utilized to detect clusters and identify their compositions, whereas TEM is applied to analyse and quantify number density and sizes of the particles during artificial ageing at 185°C. It is shown that the two techniques, TEM and APT, are complementary and a combined approach yields more detailed insight into the early stages of phase decomposition in age hardening 6xxx series alloys than possible by the sole use of either technique individually.


Author(s):  
Е.В. Докукина ◽  
Е.В. Парфенова

В работе исследуется один из возможных метод оценки риска дополнительных финансовых незапланированных затрат в рамках реализации проектов ракетно-космической отрасли, поскольку по различным причинам они не учитывались при определении технико-экономических показателей реализуемого перспективного проекта. Следовательно, предлагаемый метод позволяет на ранних стадиях проведения исследований оценить дополнительные затраты и учесть их влияние на конечные технико-экономические показатели перспективного проекта. Метод строится на основе статистического анализа затрат по этапам жизненного цикла и по проекту в целом. По итогам исследования сделан вывод о том, что риск дополнительных финансовых затрат может снизить эффективность проекта в полтора - три раза. The paper explores one of the possible methods for assessing the risk of additional unplanned costs for the implementation of a promising project. Under additional means costs that for some reason were not planned when determining the technical and economic indicators of the prospective project being implemented. The proposed method allows for the early stages of research to assess the additional costs and take into account their impact on the final technical and economic indicators of a promising project. The method is based on a statistical analysis of costs for the stages of the life cycle and for the project as a whole. The study concluded that the risk of additional costs may reduce the effectiveness of the project in one and a half to three times.


Author(s):  
Brian J. Galli

The purpose of this study is to examine the risks of using statistical tools in a project basis. A systematic search of certain academic databases has been conducted for this study. Statistical tools could be used in a project, and they should be properly planned and designed. Statistical tools include major activities, such as collecting and analyzing data, providing meaningful interpretation, and reporting findings. When dealing with statistical tools, there are several risks that may exist and impact the project either positively or negatively. This study covers a brief outline of the risk management, statistical tools, and the relationship between the two concepts. Finally, a discussion of the common type of risks that are initiated by using statistical analysis tools are provided, which could be planned, identified, and analyzed in the early stages of the project.


1986 ◽  
Vol 47 (C7) ◽  
pp. C7-489-C7-494
Author(s):  
L. V. ALVENSLEBEN ◽  
R. GRÜNE ◽  
A. HÜTTEN ◽  
M. OEHRING

1987 ◽  
Vol 48 (C6) ◽  
pp. C6-559-C6-564 ◽  
Author(s):  
M. G. Hetherington ◽  
M. K. Miller

2005 ◽  
Vol 475-479 ◽  
pp. 357-360 ◽  
Author(s):  
Shoichi Hirosawa ◽  
Tatsuo Sato

The formation of nano-scale clusters (nanoclusters) prior to the precipitation of the strengthening b” phase significantly influences two-step aging behavior of Al-Mg-Si alloys. In this work, the existence of two kinds of nanoclusters has been verified in the early stage of phase decomposition by differential scanning calorimetry (DSC) and three-dimensional atom probe (3DAP). Pre-aging treatment at 373K before natural aging was also found to form preferentially one of the two nanoclusters, resulting in the remarkable restoration of age-hardenability at paint-bake temperatures. Such microstructural control by means of optimized heat-treatments; i.e. nanocluster assist processing (NCAP), possesses great potential for enabling Al-Mg-Si alloys to be used more widely as a body-sheet material of automobiles.


1990 ◽  
Vol 186 ◽  
Author(s):  
M.G. Hetherington ◽  
J.M. Hyde ◽  
M.K. Miller

AbstractThe properties of many advanced alloys are derived from extremely fine-scale microstructures. This poses interesting questions about the measurement of composition on this scale. The phase separation of model Fe-Cr alloys has been been studied with the atom-probe. Statistical techniques have been used to estimate the composition and compare the results with the predictions of linear and non-linear theories of spinodal decomposition and the distributions obtained from Monte-Carlo calculations.


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