Microhardness Measurements Research Articles

Effect of Stacking Sequence on Mechanical Properties and Microstructural Features within Al/Cu Laminates.

The study presents a method to prepare Al/Cu laminated conductors featuring two different stacking sequences using rotary swaging, a method of intensive plastic deformation. The primary focus of the work was to perform detailed characterization of the effects of room temperature swaging on the development of microstructures, including the Al/Cu interfaces, and internal misorientations pointed to the presence of residual stress within the laminates. The results revealed that both the Al and Cu components of the final laminates with 5 mm in diameter featured fine, more or less equiaxed, grains with no dominating preferential texture orientations (the maximum observed texture intensity was 2.3 × random for the Cu components of both the laminates). This fact points to the development of dynamic restoration processes during swaging. The analyses of misorientations within the grains showed that residual stress was locally present primarily in the Cu components. The Al components did not feature a substantial presence of misorientations, which confirms the dynamic recrystallization. Tensile testing revealed that the laminates with both the designed stacking sequences exhibited comparable UTS (ultimate tensile strength) of almost 280 MPa. However, notable differences were observed with regard to the plasticity (~3.5% compared to less than 1%). The laminate consisting of Al sheath and Cu wires exhibited very low plasticity as a result of significant work hardening of Al; this hypothesis was also confirmed with microhardness measurements. Observations of the interfaces confirmed satisfactory bonding of both the metallic components.

Study of the Structural, Electrical, and Mechanical Properties and Morphological Features of Y-Doped CeO2 Ceramics with Porous Structure

In this work, ceramic samples of cerium oxide doped with yttrium were investigated. The concentration of a dopant Y(NO3)3 varied from 5 to 25 wt% in the initial charge. In the course of the experiment, a simple method was developed to obtain ceramics with a porosity of ~20% via one-step annealing in air in a muffle furnace. For comparison, samples with two annealings were also synthesized to determine the effects of pores on electrical, structural, and mechanical characteristics. The obtained samples were examined via X-ray powder diffraction, scanning electron microscopy, X-ray energy dispersive spectroscopy, Raman spectroscopy, dielectric spectroscopy, and Vickers microhardness measurements. The substitution of Ce4+ ions with Y3+ ions led to a significant decrease in the lattice parameter, average crystallite size, and average grain size, with a simultaneous increase in the lattice defectivity, dielectric constant, electrical conductivity, and microhardness values. It is shown that samples with a dopant weight fraction of 0.05–0.15 and one-step annealing have favorable electrical and mechanical characteristics for energy applications as porous materials with ionic conductivity.

Effect of Two Different Ultrafast Curing Exposure Durations on the Surface Hardness of Bulk Fill Composite - An In-Vitro Study.

The aim of the present study is to assess the microhardness of resin-based composites (RBCs) cured with ultrafast curing mode at two different exposure durations. This is an experimental in-vitro study. Forty-five cylindrical composite specimens were prepared to a dimension of 5 mm height and 4 mm diameter. Curing was done using three different exposure modes and duration with dual mode LED curing light as follows: Group I: Ultrafast curing mode for 1 second at 2300 mW/cm2 (n = 15); Group II: Ultrafast curing mode for 3 second at 2300 mW/cm2 (n = 15) and Group III: Standard exposure mode for 20 second at 1000 mW/cm2 (n = 15). Vicker's microhardness measurement was done on both the curing and non-curing sides of the specimen using a motorised diamond-faced micro-indenter (Wilson Wolpwert, Germany) using a load of 50 gram and a dwell time of 30 second. Kruskal Wallis ANOVA was used to test for difference between the three groups followed by Mann-Whitney U test for post-hoc analysis. The microhardness values of the composite cured with a conventional curing unit were significantly higher than the ultrafast cured specimens. Low-intensity conventional curing lights were found to perform better than the high-intensity ultrafast curing units.

Accelerated screening of Tax(CoCrFeMnNi)1-x and Nbx(CoCrFeMnNi)1-x high-entropy alloys

High entropy alloys are a promising group of materials with seemingly limitless and unexplored composition spaces, capable of producing extraordinary physical/mechanical properties that exceed those of conventional materials. Utilizing an additive manufacturing enabled high throughput materials discovery framework, Ta and Nb graded additions to CoCrFeMnNi are explored. Compact metallurgical Ta,Nbx(CoCrFeMnNi)1-x specimens spanning x = 0 – 100 at.% were fabricated by powder based directed energy deposition. Microstructure evolution as a function of specific Ta,Nbx(CoCrFeMnNi)1-x compositions is investigated through a combination of XRD/XRF and SEM-EDS/EBSD. Microhardness measurements were also performed to rapidly establish baseline structure–property relationships. Results revealed that eutectic microstructures were largely suppressed throughout the explored composition ranges resulting in limited ductility and extraordinary hardness.

Investigation of the surface layer of wheel steel by indentation method

The article considers methods of measurement of microhardness and modulus of elasticity of plasma hardened wheel steel by kinetic indentation method. It provides features of measurement of microhardness, modulus of hardness, elastic recovery, influencing on wear resistance of surface layers of steel. Measurement of these characteristics of material allows estimating and choosing optimum technology of surface modification by surface plasma hardening. It is confirmed that objectivity of determination of microhardness, modulus of elasticity, elastic recovery and flow stress depends on strict observance of imprint depth requirements depending on thickness of hardened layer. It is noted that in spite of the increased amount of factual information, obtained by indentation method, the physical substantiation of hardness micro-mechanisms remains poorly understood, which necessitates substantiation of physical representations of the nature of hardness of metallic materials. It is established that the measurement of microhardness, elastic modulus and elastic recovery by the kinetic indentation method is expedient to use for certification of the surface layer of plasma-hardened wheel steel according to the parameters of physical and mechanical characteristics.

The Effect of Laser Heat Treatment and Severe Shot Peening on Laser Powder Bed Fusion Manufactured AISI 316L Stainless Steel

In this study the effect of laser heat treatment (LHT) and severe shot peening (SSP) on laser powder bed fusion manufactured AISI 316L stainless steel is investigated. The effect of LHT and SSP on the hardness of the surface of the PBF-LB 316L is studied performing microhardness measurements. Microstructure is evaluated in the EBSD investigation. The residual stresses will be measured to determine the influence of LHT and SSP. The effects of LHT and SSP on tensile and bending fatigue strength will be evaluated. LHT altered the microstructure 200 µm from the surface. The grain structure on the surface was more ordered and no substructure or local strains were present. Finer grain features adjacent to the sample surface were found, which are most likely caused by effective recrystallization and fast cooling. The grain morphology was left relatively unchanged when SSP was applied on LHT surface. However, local deformation has occurred on the surface, and clear orientation gradient within grains is seen. LHT had no effect on the hardness. SSP increased the surface hardness by 205%. LHT decreased the yield or tensile strength of the PBF-LB 316L. Residual stress measurements showed that SSP induced a high compressive stress in the PBF-LB 316L. LHT and SSP significantly improved the fatigue strength of the PBF-LB manufactured 316L.

Interfacial bonding mechanism between fire exposed and functionalized carbon nanotube mortar

Reinforced concrete structures need to be repaired after exposure to fire, in which the weakness of the interfacial transition zone between the repair mortar and the old concrete substrate is a crucial problem. Carbon nanotube can be added into repair mortar to address the above-mentioned problem because of its bridging, pore filling and nucleation effects. However, the bonding mechanism of functionalized carbon nanotube repair mortar and the old concrete is not yet fully understood. Therefore, this study investigates the bonding performance between different functionalized carbon nanotube repair mortar and old mortar substrate exposed to high temperature. Firstly, to evaluate the roughness of old mortar exposed to high temperature, three-dimensional microscope and mercury intrusion porosimetry were performed in this paper. Secondly, thermogravimetric analysis and X-ray diffraction were carried out to further analyze the phase composition of the repair mortar. Thirdly, microstructure of the interfacial transition zone was investigated by electron backscatter diffraction characterization and microhardness measurements. Fourthly, the bonding mechanism of interface between new and old mortar was discussed. The results show that the surface roughness of the old mortar can gradually increase with increasing of temperature, which improves the interfacial mechanical interlocking. The functionalized carbon nanotube can reduce the content and orientation of calcium hydroxide and improve the microhardness of the interfacial transition zone. Finally, an interfacial bonding strength prediction model considering porosity and the reinforcing effects of different functionalized carbon nanotube is proposed. The findings of current study can benefit further research and application of nanomaterials in the field of structural repair and maintenance.

Thermal characterization by dilatometry tests of a ferritic-bainitic (FB) steel for automotive application

The main objective of this article is to deep the knowledge of the thermal behavior of ferrite-bainite (FB) steel in correlation with the structural aspects that justify the mechanical properties. Samples of a DP-590 steel were tested by dilatometry considering a heating rate of 0.17 °C/s, up to a temperature of 1150 °C and different cooling rates between 0.03 °C/s to 100 °C/s, in air atmosphere. The results of the thermal behaviour were correlated with a microstructural study using optical microscopy in order to establish the final proportion of ferrite and bainite that is achieved at each cooling rate considered. As the cooling rate increases, the diffusion processes are limited so that hard second phases are obtained. In this steel, the presence of bainite was corroborated. The mechanical strength evolution associated with the cooling rate was determined through microhardness measurements. On this base, the steel's continuous CCT curves was built.

FARKLI CAM İYONOMER SİMANLARIN RENK STABİLİTELERİ VE MİKROSERTLİKLERİ

Objective
 Glass ionomers are preferred in many different
 treatment procedures in dentistry due to their positive
 features. The aim of this study is to evaluate the
 color difference and microhardness values of various
 glass ionomer cement after storing them in different
 solutions.
 Material and Method
 A total of 120 samples were prepared, including 40 of
 each of the Equia Forte, AHfil Silver, and Ionofil glass
 ionomers. Each glass ionomer sample was stored in
 distilled water, cola, tea, and coffee solutions. Color
 and microhardness measurements of the specimens
 were performed before and after a week before it was
 immersed in solutions. The color measurements of the
 samples were evaluated with a spectrophotometer and
 microhardness values were evaluated with Vickers
 microhardness device. For color analysis, color
 changes (ΔE) were calculated by obtaining the values
 of L*, a*, and b* of the samples before and after a week
 after being immersed in solutions. The data obtained
 were evaluated by variance analysis (ANOVA) and
 Tukey’s test.
 Results
 Except for specimens stored in cola for AHfil Silver,
 microhardness values were increased for all materials
 immersed in test solutions. The highest color change
 was obtained in coffee for Equia Forte, in the samples
 immersed in cola for AHfil Silver and Ionophil (p

INVESTIGATION OF PHASE EQUILIBRIA AND PHYSICO-CHEMICAL PROPERTIES OF OBTAINED PHASES IN THE Sb2S3-Cr2Se3 SYSTEM

Using complex of physicochemical methods of analysis (DTA, XRD, MSA, as well as measurements of density and microhardness), the phase equilibria in the Sb2S3-Cr2Se3 system was studied and a phase diagram was constructed. It is established that the system is quasi-binary and has eutectic type T-x diagram. In the process of chemical interaction, a compound with composition Cr2Sb2S3Se3 is formed in the system. The Cr2Sb2S3Se3 compound melts incongruently at 6500C., A limited area of the solid solution based on the initial components of the system is formed. The coordinates of the eutectic formed between the α-solid solution and the Cr2Sb2S3Se3 compound is 17 mol % Cr2Se3 at 4500C. At room temperature, solid solutions based on Sb2S3 reach up to 5 mol % Cr2Se3, and based on Cr2Se3 up to – 3 mol % Sb2S3. According to the results of X-ray diffraction analysis, Cr2Sb2S3Se3 crystallizes in a tetragonal system with lattice parameters: a=16.37; c=11.69 Å, ρpuc.=5.40 q/sm3, ρX-ray=5.42 q/sm3. The temperature dependence of the electrical conductivity and thermo-EMF of the (Sb2S3)1-x(Cr2Se3)x (x=0.01; 0.02; 0.03;) solid solution has been studied

Evaluating the effect of natural, industrial juices and beverage on orthodontic bonding composite (in-vitro study)

Background: Dental erosion is a common oral condition which results due to consumption of high caloric and low pH acidic food such as carbonated drinks and fruit juices. It is expected that these food types can cause irreversible damage to dental hard tissues and early deterioration of the dental restorations. So, this study aimed to evaluate and compare the erosive potential effects of orange fruit juice and Miranda orange drink on the microhardness of an orthodontic composite material. Materials and methods: Thirty discs with a thickness of 2 mm and a diameter of 10 mm were prepared from orthodontic bonding composite. The prepared discs were equally divided into three groups (n=10). Microhardness analysis was carried out both prior to and subsequent to immersion cycles. The microhardness of the specimens underwent evaluation subsequent to immersion in the beverages for durations of 6 hours (equivalent to one day) and 42 hours (equivalent to seven days). Microhardness measurements at baseline, one day, and one week were performed utilizing the Vickers microhardness testing. Statistical analyses were carried out using repeated measure one way ANOVA test and Bonferroni post-hoc test with a level of significant p< 0.05. Results: The micro hardness of composite exposed to the selected soft drinks was significantly decreased (p< 0.05). Conclusions: Natural, industrial orange juices and Miranda can affect the micro hardness of composite. The beverage effect on the orthodontic composite based on the type of juice and the exposure time to these beverages.

Effect of temperature and rolling direction on the formability of CP2 and Ti-6Al-4V titanium materials

Abstract Pure (CP2) and alloyed titanium (Ti-6Al-4V) have an important place in biomedical and aerospace applications due to their low density and high strength properties. In this study, the effect of the formability of CP2 and Ti-6Al-4V titanium alloy at different temperatures on mechanical properties and microstructure was investigated. The hot forming process was carried out by pressing 1 mm sheet titanium plates at different temperatures on the U profile mold. Specimens along the rolling direction and perpendicular to the rolling direction were taken from the bottom the formed U-plates. Afterward, tensile tests, microhardness measurements, and changes in microstructure were examined, respectively. As a result, at high temperatures and in different rolling directions, significant changes in microstructure and mechanical properties were observed. It was determined that the best forming temperature of CP2 and Ti-6Al-4V materials along the rolling direction was 500 °C, white it is 400° for perpendicular to the rolling direction was 400 °C.

Investigation of the bleaching efficiencies of different office type bleaching techniques and the changes caused on the enamel surface.

The aim of this in vitro study is to evaluate the bleaching efficiency of 5 different office bleaching methods and the changes in enamel morphology after bleaching. In this study, 75 human molar teeth are used. The teeth are divided in half in the mesiodistal direction, and a total of 150 enamel samples are obtained. The obtained samples are split into 3 main groups to evaluate the bleaching efficiency, surface roughness, and enamel surface hardness, and each group is composed of 50 samples. Then, each main group was divided into 5 separate subgroups (n = 10) containing 5 varied bleaching techniques. Before the bleaching, color measurement with a spectrophotometer, surface roughness with a profilometer, and microhardness measurement with Vickers test device are performed. After that, different bleaching procedures are applied to the 5 subgroups formed. As a result of the statistical evaluation, it is found that there is a significant level of bleaching in all groups (p < 0.05). In the comparison between the groups, there is no remarkable divergence in terms of hardness and roughness levels (p˃0.05). In light of the findings obtained from our study, we suggest that ozone can be used as an alternative bleaching agent to hydrogen peroxide. In addition, it is discovered that the use of light activation is not necessary to increase bleaching effectiveness. Finally, we believe that enamel surface morphology may be affected after office bleaching methods; therefore, various precautions should be taken before and after bleaching.

Influence of copper interlayer on the interface characteristics of stainless steel–aluminium transitional structure in wire arc directed energy deposition

PurposeThe purpose of this study is to investigate the deposition of SS–Al transitional wall using the wire arc directed energy deposition (WA-DED) process with a Cu interlayer. This study also aims to analyse the metallographic properties of the SS–Cu and Al–Cu interfaces and their mechanical properties.Design/methodology/approachThe study used transitional deposition of SS–Al material over each other by incorporating Cu as interlayer between the two. The scanning electron microscope analysis, energy dispersive X-ray analysis, X-ray diffractometer analysis, tensile testing and micro-hardness measurement were performed to investigate the interface characteristics and mechanical properties of the SS–Al transitional wall.FindingsThe study discovered that the WA-DED process with a Cu interlayer worked well for the deposition of SS–Al transitional walls. The formation of solid solutions of Fe–Cu and Fe–Si was observed at the SS–Cu interface rather than intermetallic compounds (IMCs), according to the metallographic analysis. On the other hand, three different IMCs were formed at the Al–Cu interface, namely, Al–Cu, Al2Cu and Al4Cu9. The study also observed the formation of a lamellar structure of Al and Al2Cu at the hypereutectic phase. The mechanical testing revealed that the Al–Cu interface failed without significant deformation, i.e. < 4.73%, indicating the brittleness of the interface.Originality/valueThe study identified the formation of HCP–Fe at the SS–Cu interface, which has not been previously reported in additive manufacturing literature. Furthermore, the study observed the formation of a lamellar structure of Al and Al2Cu phase at the hypereutectic phase, which has not been previously reported in SS–Al transitional wall deposition.

Effect of silicon nitride nanoparticles on the microstructure, phase, hardness and wear properties of NiCrAlY-based nanocomposite

ABSTRACT Despite the significant oxidation resistance of NiCrAlY alloy, one of the disadvantages of this alloy is its softness and poor mechanical properties, and low wear resistance. Therefore, in this study, silicon nitride nanoparticles have been used to improve the hardness and wear resistance of the NiCrAlY alloy. The present research has examined the effect of different amounts of Si3N4 nanoparticles (1, 3, and 5 wt.%) on the structure and mechanical properties of NiCrAlY alloy. The samples were characterised by scanning electron microscopy, X-ray diffraction, and Vickers microhardness device. Initially, Si3N4 powders with 1, 3, and 5 wt% were mixed with NiCrAlY powder in a mechanical mill. Next, the powdered mixtures underwent spark plasma sintering (SPS) operations at 1100 °C for 6 min. The results of microhardness measurements showed that adding 1% Si3N4 to NiCrAlY caused the elevation of the hardness from 418 to 614 HV. Further, the sample indicated a wear rate of 1.42 × 10−5 (m3/N.m) at room temperature, under a loading force of 9.8 N, and a sliding length of 500 m. However, with an increase in the weight percentage of Si3N4 in the sample from 1 to 5 wt%, the hardness diminished from 614 to 543 HV.

Effect of Severe Shot Peening on Mechanical Properties and Fatigue Resistance of Wire Arc Additive Manufactured AISI 316L

The wire arc additive manufacturing (WAAM) technology has become very popular recently. However, the properties of printed pieces are not yet examined properly. In this paper the effect of severe shot peening (SSP) on mechanical properties of wire arc additive manufactured AISI 316L is investigated. The effect of SSP on the surface hardness of the WAAM 316L is investigated by performing microhardness measurements. Changes to the surface microstructure caused by SSP are evaluated in the EBSD investigation. The effects of SSP on tensile and fatigue strength are investigated experimentally. The EBSD analysis showed that there has been remelting of each printed layer due to the heat input from the next printed layer, and heavy epitaxial grain growth was present in the microstructure. This led to coarse columnar grain structure. Investigation of deformed SSP surface layer indicated that the main deformation type was either conventional dislocation glide or twinning. This meant that no martensite formation was present on the surface. The SSP increased the surface hardness of WAAM printed 316L by 225% and the hardened layer was 0.4 mm thick. The SSP improved the yield strength of WAAM 316L by 34%. The SSP significantly improved WAAM 316L fatigue resistance in both low-cycle and high-cycle regime.

Enamel Remineralization Efficacy of Coconut Milk and Lyophilized Coconut Extract in Different Concentrations on Demineralized Enamel Surfaces: An In-Vitro Study.

Aim The current study's objective is to determine the remineralizing efficacy of freeze-dried lyophilized coconut extract and coconut milk made from freshly grated coconut on artificial carious lesions produced by pH cycling. Materials and methods Freshly extracted coconut pulp was split into two parts. The first half was blended to obtain coconut milk, and the second part was freeze-dried and lyophilized. Tooth slabs were prepared from extracted third molar teeth. After being demineralized for 72 hours, the tooth samples were remineralized by submerging them in the appropriate remineralizing solution, which is as follows: Group 1 received 25 mL of the Remineralization solution (the control); Group 2 received 2.5 g of coconut milk and 25 mL of the solution (1:1); and Group 3 received 5 g of coconut milk and 25 mL of the solution (2:1). 2.5 g of freeze-dried, lyophilized coconut extract was given to Group 4 along with 25 mL of remineralization solution (1:1), and 5 g of freeze-dried, lyophilized coconut extract was given to Group 5 along with 25 mL of remineralization solution (2:1). Microhardness and contact angle measurements were made. An Excel spreadsheet was filled up with values from after demineralization, and after remineralization. A statistical analysis was performed using SPSS 26.0 (IBM Corp., Armonk, NY). Using descriptive statistics, the pretreatment mean values for the microhardness and contact angle of the various groups were evaluated. Post-hoc Tukey tests were utilized to compare the analytic results of the various groups. Results Among the various concentrations of freshly extracted coconut milk, the contact angle inconcentrations of 1:1 was 81.22 ± 1.62 deg, and that in concentrations of 2:1 was 88.01 ± 1.85 deg. Between the two concentrations of the lyophilized coconut extract group, the contact angle in 1:1 was 75.05 ± 2.29 deg, and in 2:1 was 71.37 ± 0.85 deg. In the coconut milk group, the value of microhardness was 261 ± 6.4 kg/cm2 at a lower concentration and 322 ±3.9 kg/cm2 at a higher concentration. In the lyophilized coconut group, the lower concentration exhibited a microhardness of 211 ±7.2 kg/cm2, whereas in the higher concentration, it was 324 ±4.04 kg/cm2. Conclusion Of the various concentrations of coconut milk and lyophilized coconut used, coconut milk at a higher concentration exhibits the highest contact angle, and the latter at a higher concentration exhibits the lowest contact angle. In both groups, high concentrations of the material exhibited high microhardness values compared to lower concentrations of the same.

Cyclic contraction-expansion extrusion (CCEE): An innovate severe plastic deformation method for tailoring the microstructure and mechanical properties of magnesium AZ91 alloy

In this study, the Cyclic Contraction-Expansion Extrusion (CCEE) process, a novel severe plastic deformation (SPD) technique, is applied to the AZ91 magnesium alloy to enhance its mechanical properties through microstructural refinement. The CCEE method combines cyclic expansion extrusion (CEE) and cyclic extrusion compression (CEC), integrating their advantages while overcoming drawbacks. The CCEE process is capable of inducing substantial plastic strain (3.38) within a single processing cycle, eliminating the need for secondary punches or a synchronized backpressure system. The process is conducted at a temperature of 300 °C, resulting in a bimodal microstructure through the dynamic recrystallization (DRX) mechanism. This microstructure consists of refined equiaxed α-Mg grains with an average size of 2.8 μm, surrounded by a network of newly nucleated α-Mg grains and Mg17Al12 particles with an average size of 500 nm in the two-pass processed sample. Results obtained from the tensile test technique indicate a significant enhancement in the ultimate tensile strength (UTS) of the AZ91 alloy, increasing from 139 MPa to 276 MPa and 290 MPa, and a notable improvement in elongation, increasing from 4% to 8% and 12% after two passes of the CCEE process. Macro-texture X-Ray diffraction (XRD) measurements reveal the formation of a pyramidal deformation texture in the one-pass sample, contributing to the UTS improvement. This texture weakens during the second pass, leading to an increase in elongation. Furthermore, microhardness measurements show an increase from HV 62 to HV 85 after the first pass of the CCEE and HV 73 after the second pass.

The Production of Marine Iron Objects in Europe Following the First Industrial Revolution: The Akko Tower Shipwreck Test Case

Four ferrous objects, a winch, a heart-shaped shackle, a deadeye strap with a futtock plate, and a stud-link chain controller, that were retrieved from the Akko Tower shipwreck were studied by different methods, including conventional metallography, light microscopy, scanning electron microscopy with energy-dispersive spectroscopy, optical emission spectroscopy, microhardness measurements, and the novel field multi-focal metallography (FMM), in order to determine their composition, microstructure, and manufacturing methods. The results of FMM agree well with conventional destructive metallography. The winch drum was made of grey cast iron and its shaft was wrought iron; the heart-shaped shackle and the deadeye strap with a futtock plate were wrought iron; and the stud-link chain controller was grey cast iron similar in composition and microstructure to the winch. All the wrought iron items revealed a similar composition and microstructure. Based on the composition, microstructure, and manufacturing processes of the four items, it is suggested that they were manufactured in the mid-nineteenth century. The high quality of these items indicates that they were produced using controlled processes, probably in the same workshop.

Investigation on microstructure and mechanical properties of 160mm thick 316L stainless steel electron-beam-welded joint

The maximum thickness of flanging position on the vacuum vessel (VV) window collar of China Fusion Engineering Test Reactor (CFETR) is 160 mm. Electron beam welding can achieve one-time penetration of the thick plate without groove and the deformation after welding is quite small. The cross section of weld was sampled for microscopic observation and mechanical properties tests to explore the difference in microstructure and performances of 160 mm thick 316 L stainless steel electron-beam-welded joints. The results showed that the weld depth-width ratio reached up to 16:1, and the microstructure of weld was composed of ferrite and austenite with different morphologies which was mainly coarse cellular crystal in heat affected zone (HAZ). The equiaxed grain orientation in the root region (denoted as “R region”) was mostly [001] and the columnar grain orientation along the temperature gradient was mostly [101]. The microstructure along the depth direction was quite different, which was mainly related to the solidification mode and composition overcooling. The high strength (YS=715.22 MPa) of R region was due to the smaller temperature gradient and the larger cooling rate, the position of fracture suggested that the strength of weld was higher than that of the base metal. The microhardness measurement results showed that the hardness increased gradually along the depth direction of weld (Top:156.5 HV, Root: 238.7 HV) and fluctuated along the width direction. The tensile properties along the thickness direction exhibited a trend of decreasing first and then increasing, which was mainly related to the characteristics of electron beam deep penetration welding and the difference of grain structure along the thickness direction.