Experimental Study of Mechanical Properties of 30SiMn2MoVA Steel Gun Barrel Processed by Cold Radial Forging

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Yuzhao Yang ◽  
Lixia Fan ◽  
Cheng Xu ◽  
Xuehua Dong

Abstract This work focused on the mechanical properties of 30SiMn2MoVA high strength steel gun barrel processed by cold radial forging. Three states of the tube made of this material (the state without forging, the as-forged state without annealing, and the as-forged state with annealing) were chosen to compare the axial and circumferential mechanical properties. As a result, anisotropy was found at as-forged state. The circumferential mechanical properties were inferior to the axial. The circumferential yield and tensile strength were about 150 MPa lower than the axial after forging, and the axial elongation was 155% higher than the circumferential. Even after annealing, the circumferential elongation cannot be restored to the same level as the state without forging. The reasons for anisotropy were investigated by the microstructure. The banded structure along the axial direction was observed in the forged barrel. Meanwhile, the crystalline grains of the forged gun barrel had the highest intensity of {111}〈110〉 texture which meant the grains had obvious preferential orientation. The relationship between crystallographic texture and yield strength was analyzed based on the Schmid factor. Additionally, the elastic limit internal pressure of anisotropic gun barrel was calculated, and it was lower than that under isotropic condition.

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 76 ◽  
Author(s):  
Zheng Wang ◽  
Jin-Guo Wang ◽  
Ze-Yu Chen ◽  
Min Zha ◽  
Cheng Wang ◽  
...  

Forming magnesium alloys with rare earth elements (La, Gd, Nd, Y, Ce) is a routine method for modifying their microstructure and properties. In the present work, the effect of Ce addition on the microstructure evolution and the mechanical properties of as-extruded Mg-8Al-0.5Zn (AZ80) alloy was investigated. All of the extruded AZ80-xCe (x = 0, 0.2, 0.8 and 1.4 wt %) alloys exhibited equiaxed grains formed by fully dynamic recrystallization, and the grain size of the extruded AZ80 alloy was remarkably reduced by ~56.7% with the addition of 1.4 wt % Ce. Furthermore, the bulk-shaped Al4Ce phase formed when Ce was first added, with the Ce content rising to 0.8 wt % or higher, and Al4Ce particles in both the nano- and micron sizees were well distributed in the primary α-Mg matrix. The area fraction of the Al4Ce particles expanded with increasing Ce content, providing more nuclei for dynamic recrystallization, which could contribute to the grain refinement. The results of the tensile tests in this study showed that Ce addition effectively improved the room temperature formability of the as-extruded AZ80 alloy, without sacrificing strength. The significantly improved mechanical properties were ascribed to excellent grain refinement, weakened texture strength, an increased Schmid factor, and a reduced area fraction of low-angle grain boundaries, all resulting from Ce addition to the as-extruded AZ80 alloy. The contribution of the nano-Al4Ce precipitates on improving the mechanical properties was also discussed in this paper.


2018 ◽  
Vol 80 (6) ◽  
Author(s):  
D. N. Nguyen ◽  
A. T. Hoang ◽  
X. D. Pham ◽  
M. T. Sai ◽  
M. Q. Chau ◽  
...  

This paper investigates a high electrical conductivity and high strength of alloys based on Cu-Ni-Si system It proclaimed the results of the effect of tin (Sn) component on the mechanical properties and microstructure of Cu-Ni-Sn alloy. The conditions for processing the Cu-Ni-Si alloy were presented, the analysis of microstructure and mechanical properties after heat treatment was examined by X-ray, SEM, EDS and specialized machines. The results showed that with 3% mass of Sn added into the Cu-Ni-Sn alloy along with heat treatment and deformation, the hardness value reached the range of 221-240HV, the tensile strength and elastic limit reached around 1060MPa and 903MPa respectively. However, after heat treatment and deformation for the Cu-Ni-Sn alloy based on 6% mass of Sn, the hardness value reached the range of 221-318HV, the tensile strength and elastic limit were respectively 222MPa and 263MPa higher than those of the Cu-Ni-Sn alloy with 3% mass of Sn. The result from X-ray analysis showed the deflection of peaks. Nonetheless, the new phases were not observed in SEM and EDS, contrariwise, generated modular structure was considered as the proof of the Spinodal cluster. This fact might be explained by two mechanisms: deformation mechanism and Spinodal decomposition.


1990 ◽  
Vol 195 ◽  
Author(s):  
H. K. Niculescu ◽  
P. J. Gielisse ◽  
Y. S. Hascicek ◽  
L. R. Testardi

ABSTRACTIn this paper an experimental study of YBa2Cu3O7−x/silver composites is presented and the relationship between microstructure, superconducting and mechanical properties is discussed. Silver contents ranging from 0 to 17 vol% fell all below the percolation treshold. X-ray and Wavelength Dispersive Spectrometry analyses indicate that Ag remains in a free state, and is located mainly at the grain boundaries. A tenfold increase in Jc. and a more than twofold increase in strength are the benefits of the improved microstructure of silver composites. The Tc remains unaffected.


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