Method to increase the toughness of aluminum-lithium alloys at cryogenic temperatures

A method to increase the toughness of the aluminum-lithium alloy C458 and similar alloys at cryogenic temperatures above their room temperature toughness is provided. Increasing the cryogenic toughness of the aluminum-lithium alloy C458 allows the use of alloy C458 for cryogenic tanks, for example for launch vehicles in the aerospace industry. A two-step aging treatment for alloy C458 is provided. A specific set of times and temperatures to age the aluminum-lithium alloy C458 to T8 temper is disclosed that results in a higher toughness at cryogenic temperatures compared to room temperature. The disclosed two-step aging treatment for alloy 458 can be easily practiced in the manufacturing process, does not involve impractical heating rates or durations, and does not degrade other material properties

On a Generalisation of Uniform Distribution and its Properties

Nadarajah et al.(2013) introduced a family life time models using truncated negative binomial distribution and derived some properties of the family of distributions. It is a generalization of Marshall-Olkin family of distributions. In this paper, we introduce Generalized Uniform Distribution (GUD) using the approach of Nadarajah et al.(2013). The shape properties of density function and hazard function are discussed. The expression for moments, order statistics, entropies are obtained. Estimation procedure is also discussed.The GDU introduced here is a generalization of the Marshall-Olkin extended uniform distribution studied in Jose and Krishna(2011)

Structure-property Correlations in Al 7050 and Al 7055 High-strength Aluminum Alloys

The 7XXX series age-hardenable high-strength aluminum alloys find useful applications in the field of aerospace engineering. Constant efforts are being made to tailor the mechanical and corrosion properties of these alloys as per requirements for a particular application. These properties are a function of factors like microstructure, chemical composition and processing parameters. An effort has been made to collate the information available from different studies conducted on alloys Al 7050 and Al 7055. Databases were created to consolidate the information about microstructure, mechanical properties and corrosion behavior for the two alloys. Existing models were utilized to predict strength and fracture toughness for these alloys and these models were validated using experimental values and a qualitative evaluation was made for the corrosion behavior of these alloys. Available data were utilized to prepare maps that are intended to serve as guides to design aluminum alloys with desired combination of properties

Microstructure and Mechanical Behavior of Friction Stir Processed Ultrafine Grained Al-Mg-Sc Alloy

Twin-roll cast (TRC) Al-Mg-Sc alloy was frictionstir processed (FSP) to obtain ultrafine grained (UFG) microstructure. Average grain size of TRC alloy in as-received (AR) condition was 19.0 ± 27.2 μm. The grain size reduced to 0.73 ± 0.44 μm after FSP. About 80% of the grains were smaller than 1 μm in FSP condition. FSP resulted into 80% of the grain boundaries to have high angle grain boundary (HAGBs) character. Uniaxial tensile testing of UFG alloy showed an increase in yield strength (YS) and ultimate tensile strength (UTS) (by ∼100 MPa each) of the alloy with a very marginal decrease in total and uniform elongation (total - 27% in AR and 24% in UFG and uniform - 19% in AR and 14% in UFG). A theoretical model predicted that the grain refinement cannot take place via discontinuous dynamic recrystallization. Zener pinning model correctly predicted the grain size distribution for UFG alloy. From work hardening behaviors in both the conditions, it was concluded that grain boundary spacing is more important than the character of grain boundaries for influencing extent of uniform deformation of an allo

Critical Grain Size for Change in Deformation Behavior in Ultrafine Grained Al-Mg-Sc Alloy

Experimental evaluation of critical grain size for the change in deformation behavior from strain hardening to strain softening in ultrafine grained (UFG) Al-Mg-Sc was carried out. UFG alloy was processed using friction stir processing (FSP). Two different average grain sizes were obtained by changing the FSP parameters. UFG alloy with grain size larger than the subgrain size showed sufficient strain hardening during tensile testing, whereas smaller grain size material exhibited strain softening

The Effect of Friction Stir Processing on the Microstructure and Mechanical Properties of Equal Channel Angular Pressed 5052Al Alloy Sheet

In this study, equal channel angular pressed (ECAP) 5052Al alloy sheet was friction stir processed (FSP). This was carried out to understand the effect of FSP on the microstructure and mechanical properties of the ECAP sheet. FSP led to further grain refinement and a tighter distribution of grains. Fraction of high-angle grain boundaries changed from 15% in ECAP condition to more than 70% after FSP. Although FSP caused lowering of yield strength (YS) and ultimate tensile strength (UTS), it resulted into a substantial improvement in uniform deformation region of the tensile sample (from 1.3% in as-received condition to 12.9% in FSP condition). Strain hardening rate (SHR) analysis showed lowering of recovery rate on FSP. A static grain growth model correctly predicted the average grain size obtained after FSP. Existing grain boundary, solid solution, and dislocation strengthening models were used to estimate the YS of 5052Al alloy in both the conditions. The strengthening model was able to predict the YS of the alloy in as-received and FSP conditions very well

Smart Water Resource Management Using Artificial Intelligence—A Review

Water management is one of the crucial topics discussed in most of the international forums. Water harvesting and recycling are the major requirements to meet the global upcoming demand of the water crisis, which is prevalent. To achieve this, we need more emphasis on water management techniques that are applied across various categories of the applications. Keeping in mind the population density index, there is a dire need to implement intelligent water management mechanisms for effective distribution, conservation and to maintain the water quality standards for various purposes. The prescribed work discusses about few major areas of applications that are required for efficient water management. Those are recent trends in wastewater recycle, water distribution, rainwater harvesting and irrigation management using various Artificial Intelligence (AI) models. The data acquired for these applications are purely unique and also differs by type. Hence, there is a dire need to use a model or algorithm that can be applied to provide solutions across all these applications. Artificial Intelligence (AI) and Deep Learning (DL) techniques along with the Internet of things (IoT) framework can facilitate in designing a smart water management system for sustainable water usage from natural resources. This work surveys various water management techniques and the use of AI/DL along with the IoT network and case studies, sample statistical analysis to develop an efficient water management framework