Effect of Gd content on microstructure and mechanical properties of Mg–Gd–Y–Zr alloys under peak-aged condition

Cu-Cr-Zr-Ti alloys are widely used for fabrication of thrust chamber in liquid rocket engines, because of their high thermal conductivity and adequate strength. The alloy should be used in peak-aged condition to achieve the best combination of strength and conductivity. However, realization of final component involves forming and brazing operations which limit the usage of the alloy in peak aged condition. Therefore, an attempt has been made to study the effect of the simulated brazing treatment on the microstructure and mechanical properties using optical microscopy, electron microscopy, mechanical testing and hardness measurement. The high temperature brazing treatments resulted in tremendous grain growth. The measured hardness is observed to be in line with the grain size of the specimens. The hardness and tensile strength decreased in samples subjected to simulated brazing cycle, implying requirement for a post braze treatment. After the post brazing treatment the optimum mechanical properties have been achieved at room temperature. Low ductility was observed at 600°C in the samples subjected to simulated brazing cycle.

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Microstructure and Mechanical Properties of the Spray-Deposited Al-10.8Zn-2.8Mg-1.9Cu Alloy at Various Aging Conditions

Materials Science Forum ◽

10.4028/www.scientific.net/msf.561-565.809 ◽

2007 ◽

Vol 561-565 ◽

pp. 809-812

Author(s):

Feng Wang ◽

Bai Qing Xiong ◽

Yon Gan Zhang ◽

Bao Hong Zhu ◽

Hong Wei Liu ◽

...

Keyword(s):

Mechanical Properties ◽

High Resolution Electron Microscopy ◽

Tensile Tests ◽

Aged Condition ◽

Aging Condition ◽

Microstructure And Mechanical Properties ◽

Peak Aged Condition ◽

Resolution Electron ◽

Aging Conditions ◽

Peak Aged

In this paper, Al-10.8Zn-2.8Mg-1.9Cu alloy was synthesized by the spray atomization and deposition technique. The microstructure and mechanical properties of the spray deposited alloy at various aging conditions (T6, T73 and RRA treatment) were studied using high-resolution electron microscopy, selected area diffraction, and tensile tests. The results indicate that the two types of GP zones, GPI and GPII zones are major precipitates for the alloy under peak-aged condition. The peak UTS and YS values achieved at an ageing temperature of 120 °C was 818 MPa and 793 MPa. Under two-step aging condition, the GP zones and η’ are major precipitates for the alloy, the discontinuous grain boundary precipitates are favorable to SCC resistance in over-aged condition, which reduces its strength 58 MPa(about 7%) comparing to the peak-aged condition. RRA treatment decreased ultimate tensile strength 25 MPa (about 3%) in values compared with the alloy at T6 condition.

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Excellent age hardenability with the controllable microstructure of AXW100 magnesium sheet alloy

Scientific Reports ◽

10.1038/s41598-020-79390-z ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Sumi Jo ◽

Lawrence Whitmore ◽

Sangkyu Woo ◽

Ainhoa Urrutia Aramburu ◽

Dietmar Letzig ◽

...

Keyword(s):

Mechanical Properties ◽

Texture Evolution ◽

Grain Structure ◽

Aged Condition ◽

Tem Analysis ◽

Fine Grain ◽

Peak Aged Condition ◽

Peak Aged ◽

Grain Boundary Pinning ◽

Weak Texture

AbstractAge-hardenability and corresponding improvement of the mechanical properties of Mg–1Al–0.7Ca and Mg–1Al–0.7Ca–0.7Y alloy sheets are addressed with respect to the microstructure and texture evolution during thermomechanical treatments. A fine grain structure and weak texture with the basal pole split into the sheet transverse direction are retained in the Mg–1Al–0.7Ca–0.7Y sheet even after the homogenization at 500 °C, due to the grain boundary pinning by Y-containing precipitates possessing a high thermal stability. Contrarily, the Mg–1Al–0.7Ca sheet shows a coarse microstructure and basal-type texture after the homogenization. The peak-aged condition is attained after the aging at 250 °C for 1800 s of both homogenized sheets, while the Y-containing sheet shows a higher hardness than the Mg–1Al–0.7Ca sheet. TEM analysis and thermodynamic calculation show the formation of metastable precipitates composed of Al, Ca, Y and Mg in the Mg–1Al–0.7Ca–0.7Y sheet at the homogenized and peak-aged conditions. A significant increase in the yield strength is obtained in the peak-aged condition from 162 MPa after the homogenization to 244 MPa, which arises from the increased size and number density of the precipitates. The high age-hardenability of the Mg–1Al–0.7Ca–0.7Y sheet attributes to the superior mechanical properties with an improved ductility promoted by the weak texture.

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Aging Behavior in 15-5 PH Precipitation Hardening Martensitic Stainless Steel

Materials Science Forum ◽

10.4028/www.scientific.net/msf.710.483 ◽

2012 ◽

Vol 710 ◽

pp. 483-488 ◽

Cited By ~ 4

Author(s):

V. Anil Kumar ◽

M.K. Karthikeyan ◽

Rohit Kumar Gupta ◽

F. Gino Prakash ◽

P. Ram Kumar

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Stainless Steel ◽

Precipitation Hardening ◽

Martensitic Stainless Steel ◽

Low Carbon ◽

Aged Condition ◽

Aging Behavior ◽

Peak Aged Condition ◽

Peak Aged

15-5 PH stainless steel is strengthened by precipitation of copper rich phases in a low carbon body centred cubic (b.c.c) lath martensitic matrix. Microstructures developed in aerospace grade 15-5PH precipitation-hardened stainless steel with different aging heat treatments have been studied. An attempt has been made to correlate the microstructural observations with the mechanical properties in different aging regimes. The overaging treatment imparts excellent ductility with a compromise in strength in peak aged condition to overaged condition the tune of 300 MPa in both tensile and yield strength. Hardness and tensile strength showed a similar decreasing trend with increase in aging temperature.

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