Annealing Effects in Cast Commercial Aluminium Al–Mg–Zn–Cu(–Sc–Zr) Alloys

Aluminum-lithium alloys have a low density and high strength to weight ratio. They are being developed for the aerospace industry.The high strength of Al-Li can be attributed to precipitation hardening. Unfortunately when aged, Al-Li aquires a low ductility and fracture toughness. The precipitate in Al-Li is part of a sequence SSSS → Al3Li → AlLi A description of the phases may be found in reference 1 . This paper is primarily concerned with the Al3Li phase. The addition of Zr to Al-Li is being explored to find the optimum in properties. Zirconium improves fracture toughness and inhibits recrystallization. This study is a comparision between two Al-Li-Zr alloys differing in Zr concentration.Al-2.99Li-0.17Zr(alloy A) and Al-2.99Li-0.67Zr (alloy B) were solutionized for one hour at 500oc followed by a water quench. The specimens were then aged at 150°C for 16 or 40 hours. The foils were punched into 3mm discs. The specimens were electropolished with a 1/3 nitric acid 2/3 methanol solution. The transmission electron microscopy was conducted on the JEM 200CX microscope.

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“Cavity” formation in superplastically deformed aluminium alloys

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100177921 ◽

1990 ◽

Vol 48 (4) ◽

pp. 958-959

Author(s):

A. Cziráki ◽

E. Ková-csetényi ◽

T. Torma ◽

T. Turmezey

Keyword(s):

Grain Boundaries ◽

Aluminium Alloys ◽

Superplastic Deformation ◽

Volume Fraction ◽

Superplastic Forming ◽

Polished Surface ◽

Cavity Formation ◽

Stress Concentrations ◽

Electron Microscopic ◽

Commercial Aluminium

It is known that the formation of cavities during superplastic deformation can be correlated with the development of stress concentrations at irregularities along grain boundaries such as particles, ledges and triple points. In commercial aluminium alloys Al-Fe-Si particles or other coarse constituents may play an important role in cavity formation.Cavity formation during superplastic deformation was studied by optical metallography and transmission scanning electron microscopic investigations on Al-Mg-Si and Al-Mg-Mn alloys. The structure of particles was characterized by selected area diffraction and X-ray micro analysis. The volume fraction of “voids” was determined on mechanically polished surface.It was found by electron microscopy that strongly deformed regions are formed during superplastic forming at grain boundaries and around coarse particles.According to electron diffraction measurements these areas consist of small micro crystallized regions. See Fig.l.Comparing the volume fraction and morphology of cavities found by optical microscopy a good correlation was established between that of micro crystalline regions.

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THE STRUCTURE OF AMORPHOUS Ni-Zr ALLOYS

Le Journal de Physique Colloques ◽

10.1051/jphyscol:1985825 ◽

1985 ◽

Vol 46 (C8) ◽

pp. C8-181-C8-185

Author(s):

A. E. Lee ◽

S. Jost ◽

Ch. N.J. Wagner ◽

L. E. Tanner

Keyword(s):

Zr Alloys

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Experimental and Theoretical Comparable Study of Pure and Zinc Porphyrin Surface Modified ZnO Nanorod Arrays for Hybrid Solar Cell Applications

10.32792/utq/utjsci/vol7/2/26 ◽

2020 ◽

pp. 114-119

Keyword(s):

Solar Cell ◽

Electrochemical Impedance ◽

Hybrid Solar Cell ◽

Cell Performance ◽

Solar Cell Performance ◽

Solar Cell Efficiency ◽

Cell Efficiency ◽

Annealing Effects ◽

Vertically Aligned ◽

Surface Modified

Experimental and theoretical study Porphyrin-grafted ZnO nanowire arrays were investigated for organic/inorganic hybrid solar cell applications. Two types of porphyrin – Tetra (4-carboxyphenyle) TCPP and meso-Tetraphenylporphine (Zinc-TPP)were used to modify the nanowire surfaces. The vertically aligned nanowires with porphyrin modifications were embedded in graphene-enriched poly (3-hexylthiophene) [G-P3HT] for p-n junction nanowire solar cells. Surface grafting of ZnO nanowires was found to improve the solar cell efficiency. There are different effect for the two types of porphyrin as results of Zn existing. Annealing effects on the solar cell performance were investigated by heating the devices up to 225 °C in air. It was found that the cell performance was significantly degraded after annealing. The degradation was attributed to the polymer structural change at high temperature as evidenced by electrochemical impedance spectroscopy measurements.

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