Dynamic Behaviour of Selective Laser Melted 316L Steel - Mechanical Properties and Microstructure Changes
2
Citation
22
Reference
10
Related Paper
Citation Trend
Abstract:
316L steel specimens with three different shear zones made by SLM (Selective Laser Melting) were subjected to dynamic tests using the Split Hopkinson Pressure Bar method. The effect of high-speed deformation on changes in microstructure was analyzed. In addition, the stress-strain relationship was determined from the SHPB results. To visualize the deformation process of the specimens during the tests, a camera with a high frame rate was used. It was shown that as the plastic deformation increases, the hardness of the material increases. Microstructural analysis of dynamically loaded areas revealed numerous defects. Twinning was found to be the main deformation mechanism. Large plastic deformation and many other microstructural changes such as shear bands, cracks and martensite nucleation were also observed.Keywords:
Split Hopkinson Pressure Bar
Deformation bands
Deformation mechanism
In order to investigate the microstructure evolution under high strain rate deformation, extruded AZ31B magnesium alloy was impacted by split Hopkinson compression bars at the strain rates of 496-2 120 s-1. The microstructures of the specimens were observed by optical microscopy. The results show that the stress—strain curves of AZ31B magnesium alloy are almost overlap under different strain rates, implying that the stress of AZ31B magnesium is not sensitive to the strain rate. The deformation microstructure analysis demonstrates that the microstructure is sensitive to the strain rate. When the strain rate is relatively low, the microstructure is dominated by intense twinning. With increasing strain rate, the volume fraction of twinning decreases. The microstructure analysis demonstrate that at relatively low strain rate, the deformation mechanism of AZ31B magnesium alloy under impact load is twinning, while the strain rate increases to 2 120 s-1, the prismatic slip and pyramidal slip may be active to accommodate with the deformation except twinning.
Deformation mechanism
Cite
Citations (2)
Split Hopkinson Pressure Bar
Delamination
Breakage
Cite
Citations (22)
Effects of the contact geometry on high strain rate failure behavior of woven graphite/epoxy composites are presented. Compressive split Hopkinson pressure bar was used for high strain rate experiments. Woven graphite/epoxy composites were loaded transversely using two different contact geometries at the impact energies of 67 J and 163 J. It is observed that smaller contact area gives higher damage, resulting in higher energy absorption, elastic modulus and strain rate and peak stress in the specimens.
Split Hopkinson Pressure Bar
Contact Geometry
Bar (unit)
Strain (injury)
Cite
Citations (0)
Deformation mechanism
Deformation bands
Cite
Citations (16)
Split Hopkinson Pressure Bar
Metal matrix composite
Strain (injury)
Cite
Citations (26)
The mechanical response and deformation mechanisms of TB17 titanium alloy were studied at room temperature by the split-Hopkinson pressure bar test. The ultimate compression strength increases from 1050 MPa to 1400 MPa, as the strain rate increases from 2000 s−1 to 2800 s−1. The adiabatic shear failure occurred at strain rate 2800 s−1. When the strain rate was 2000 s−1, only {10 9 3}<331>β type II high index deformation twins, a small number of α” martensite, and interfacial ω phase were detected. When the strain rate was 2400 s−1 and above, multiple deformation mechanisms, including the primary {10 9 3}<331>β type II high index deformation twins, secondary {332}<113>β deformation twins, and α” martensite were identified. The deformation mechanism changes from primary deformation twins and α” martensite to multiple deformation mechanisms (primary and secondary deformation structure) with the increase of strain rates.
Split Hopkinson Pressure Bar
Deformation mechanism
Strain (injury)
Adiabatic shear band
Portevin–Le Chatelier effect
Titanium alloy
Cite
Citations (4)
Effects of the loading direction on high strain rate behavior of cylindrical woven graphite/epoxy composites are presented. Compressive split Hopkinson pressure bar (SHPB) was used for high strain rate experiments. Cylindrical specimens were loaded diametrically and transversely at the impact energies of 67 J, 163 J, and 263 J. Micro Laser Raman spectroscopy and scanning electron microscopy (SEM) were used for surface characterization. It is observed that diametrically loaded specimens show permanent plastic deformation with high ductility resulting in a catastrophic failure while transversely loaded specimens exhibit viscoplastic deformation with some recoverable damage. As a result of this, Raman peak shifted to higher values for the diametrically loaded fibers whereas almost no change was observed in the Raman shift of transversely loaded fibers.
Split Hopkinson Pressure Bar
Ductility (Earth science)
Bar (unit)
Cite
Citations (2)
Deformation twinning is an important deformation mechanism in a variety of materials, including metals and ceramics. This deformation mechanism is particularly important in low-symmetry hexagonal close-packed (hcp) metals such as Magnesium (Mg), Zirconium (Zr) and Titanium (Ti). Extension twins in Mg, Zr and Ti can accommodate considerable plastic deformation as they grow. Thus, the rate and the mode of twinning greatly influences the mechanical behavior including strength and ductility. Herein, we study deformation twinning in terms of nucleation, twinning mode and variant selection as a function of strain rate in Mg single crystal (considered as a model material). We show that twin variant selection is sensitive to the loading rate, with more twin variants nucleating at the dynamic strain rates. Low Schmid factor twin variants (one of them being a double extension twin variant) were also found at the dynamic strain rates. Further at high strain rates, the first twins generated do not thicken beyond a critical width. Instead, plasticity proceeds with nucleation of second generation twins from the primary twin boundaries. The rates of area/volume fraction evolution of both generations of twins are found to be similar.
Deformation mechanism
Ductility (Earth science)
Cite
Citations (6)
Deformation twinning is an important deformation mechanism in a variety of materials, including metals and ceramics. This deformation mechanism is particularly important in low-symmetry hexagonal close-packed (hcp) metals such as Magnesium (Mg), Zirconium (Zr) and Titanium (Ti). Extension twins in Mg, Zr and Ti can accommodate considerable plastic deformation as they grow. Thus, the rate and the mode of twinning greatly influences the mechanical behavior including strength and ductility. Herein, we study deformation twinning in terms of nucleation, twinning mode and variant selection as a function of strain rate in Mg single crystal (considered as a model material). We show that twin variant selection is sensitive to the loading rate, with more twin variants nucleating at the dynamic strain rates. Low Schmid factor twin variants (one of them being a double extension twin variant) were also found at the dynamic strain rates. Further at high strain rates, the first twins generated do not thicken beyond a critical width. Instead, plasticity proceeds with nucleation of second generation twins from the primary twin boundaries. The rates of area/volume fraction evolution of both generations of twins are found to be similar.
Deformation mechanism
Ductility (Earth science)
Cite
Citations (8)
The high strain rate compressive properties of UHMWPE interlaced biaxial weft knitted(IBWK) fabrics/ vinyl ester resin composites were carried out in split Hopkinson pressure bar(SHPB).The strain rate effect and energy Absorption of composites were studied.The results indicate that the compressive performances of composites are improved after plasma modification,and 100W is an appropriate treating condition for discharge power.UHMWPE IBWK composite is a strain rate sensitive material in a certain extent:the peak stress,compressive modulus and specific fracture strain energy density increase with the increase of strain rate.Attribute to the knitted loop and the intertexture of warp and weft yarns,IBWK structure shows good impact resistance.
Split Hopkinson Pressure Bar
Strain (injury)
Cite
Citations (1)