Combined Effects Of Grain Refinement Research Articles

The effect of shot peening on the contact fatigue performance of C40 steel gears after laser surface melting

In this paper, shot peening (SP) was employed as a post-processing technique for the laser surface melted (LSMed) gear. The aim was to improve the contact fatigue performance of laser surface melting+shot peened (LSMSPed) gears. The microstructure, surface roughness, residual stress, microhardness of C40 steel gears before and after SP treatment were characterized using scanning electron microscopy, x-ray diffraction stress analyzer, contour measuring instrument, and hardness tester. Fatigue test of gear was carried out with a Forschungsstelle für Zahnräder und Getriebebau (FZG) testing machine. Following the laser surface melting (LSM) treatment, a molten layer was observed on the gear teeth surface. The experimental results indicated that SP induced a hardened layer with a certain thickness and plastic deformation on the surface of LSMed gears. Importantly, as the SP parameters increased, there’s a corresponding reduction in both the average grain diameter and the maximum grain diameter. The reduction was most pronounced when the shot diameter reached its maximum value. It’s worth noting that once the optimal threshold for SP parameters is surpassed, the residual compressive stress and microhardness on the LSMSPed gear surface do not exhibit a continuous growth trend. Furthermore, the rise in SP parameters resulted in a gradual increase in the surface roughness of LSMSPed gears, albeit to varying degrees. In light of the combined effects of grain refinement, residual compressive stress, microhardness, and surface roughness, the contact fatigue performance of LSMSPed gears improved with increasing SP parameters. Notably, when comparing the contact fatigue life of LSMed gears with that of LSMSPed gears, we observed a substantial enhancement. However, it’s essential to highlight that when the shot diameter reaches its maximum value, the contact fatigue life of the LSMSPed gear, somewhat unexpectedly, decreased. It emphasized to a certain extent the influence of surface roughness on the contact fatigue performance of LSMSP gears.

The feasibility of resistance seam welding as an additive manufacturing technology for Al 1060

Resistance seam welding additive manufacturing (RSAM) is a new solid-state additive manufacturing technique that utilizes pulsed current and pressure to welding powders layer by layer. In this study, Al1060 powder was employed as the raw material to prepare R0 and R10 samples through RSAM technology and subsequent repeated welding processes, respectively. The results showed that, compared to R0, the grain size of the R10 sample decreased from 34.3 μm to 8.7 μm, and the dislocation density increased from 4.355 × 1014 to 9.436 × 1014 m−2. Additionally, due to the additional heat and pressure from repeated welding, the porosity decreased from 0.998% to 0.017%, the ultimate tensile strength and elongation improved from 63.5 ± 0.5 MPa and 4.5 ± 0.1% in R0 to 93.3 ± 0.5 MPa and 34.3 ± 0.1% in R10. The improvement in mechanical properties is primarily due to the combined effects of grain refinement, dislocation strengthening, and pore self-healing. This study introduces a feasible new approach for additive manufacturing of aluminum alloys and other materials that is difficult to be additively manufactured by other methods.

Nanocrystallization and strengthening of Mg-Dy-Zr alloys by room temperature rotary swaging

In this study, bulk Mg-Dy-Zr alloys with an average grain size of 78.8 nm and a diameter of 12.1 mm were prepared by room temperature rotary swaging (RTRS). The evolution of the microstructure and texture during the grain refinement process was investigated using electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). The results show that the original texture consisting of arbitrarily oriented recrystallized grains and ED∥[10 0] deformed grains is transformed into an ED∥[10 0] texture after the alloy processed by RTRS. The formation of nanograins is induced by a large number of tensile twins, deformation bands, and dislocation arrays synergistically adapting to the strain. The yield strength and ultimate tensile strength of the nanograin alloys obtained are substantially increased to 281% and 190% of those of the as-extruded alloys. The strength improvement of the alloys is a result of the combined effect of grain refinement and dislocation strengthening, in which nanograin strengthening dominates.

Unraveling the effects of nano-grained microstructure on mechanical behavior, corrosion, and in vitro biocompatibility of 316L austenitic stainless steel

Nanograins are often beneficial in achieving better cytocompatibility for metallic implants. In this work, we have achieved grains from the micro to nano range in 316L austenitic stainless steel by a combination of cryo-rolling (50%, 70%, and 90% thickness reduction) followed by annealing (750–1000 °C for 2–20 min). The combined effect of grain refinement along with texture on its mechanical, corrosion, and in vitro cellular behavior was thoroughly investigated. Microstructural observations revealed nanograins formation (grain size = 144 nm) only for the 90CRA sample, whereas grain refinement in the micron range was observed for 0-70CRA samples. Electron backscatter diffraction (EBSD) studies showed fully austenitic structures for all the annealed samples while low Kernel Average Misorientation (KAM) values indicated strain-free microstructures. Orientation distribution function (ODF) maps showed the presence of strong γ-fiber (<111>||ND) and weak α-fiber (<110>||ND) in the 90CRA sample. The grain refinement led to an increase in the yield strength and ultimate tensile strength from 470.6 ± 16.21 MPa and 858.35 ± 31.82 MPa (0CRA) to 1662.06 ± 58.44 MPa and 2112.3 ± 51.62 MPa (90CRA), respectively. The potentiodynamic polarization study revealed that the corrosion rate of the 90CRA sample was about eight times less than that of the 0CRA sample. This was further corroborated by Mott-Schottky analysis, which showed a lowering of both acceptor and donor densities with the reduction in grain size. The evolution of a strong <111> texture during cryo-rolling contributed towards enhanced corrosion resistance of nano-grained 316L. Furthermore, grain refinement improved wettability, which in turn led to better cell proliferation and differentiation. At all culture days, MC3T3-E1 cell proliferation and differentiation were considerably higher for nano-grained 316L micron-sized counterparts. Thus, grain refinement to the nano range is an effective technique for the property enhancement of biomedical implants.

Preparation of Al-Ti-Sc master alloys and refining effects on the 6016 aluminum alloy

The 6016 aluminum alloy has good plasticity but low strength. In this work, Al-Ti-Sc master alloy was prepared by thermite reduction method in order to obtain an effective grain refiner with a simplified preparation process and a reduced cost. The refining effects of the ternary master alloy on the 6016 aluminum alloy were checked to improve the strength and plasticity simultaneously. The chemical reactions during the preparation process of the Al-Ti-Sc master alloy was studied by thermodynamic software of HSC 6.0. The content of Sc and Ti in the master alloy reaches 2.48 wt% and 1.4 wt%, respectively, on proper experimental conditions, and the main phases of the master alloys are α-Al and Al3(Sc,Ti) phase. In the refined alloys, the average grain size can reach 27 μm, and the ultimate tensile strength and the elongation after fracture reaches 280 MPa and 35% in cast state, respectively. Compared to the pristine 6016 aluminium alloy, the significantly enhanced strength and good plasticity of the refined alloys contribute to the combined effects of grain refinement and precipitated phase strengthening. For the fracture of low doped alloys, originates from cleavage fracture mechanisms, and for the ones with high dosages, ductile fracture becomes dominant.

A Rolled Mg–8Al–1Sm–1Zn Alloy with High‐Strength Ductility via Single‐Pass Liner Rolling

In this article, the microstructure and mechanical properties of Mg–8Al–1Sm–1Zn alloy prepared by multi‐pass conventional rolling and single‐pass liner rolling are investigated. The alloy is subjected to multi‐pass conventional rolling with a cumulative deformation of 60% and single‐pass liner rolling with a deformation of 60% after solution‐treated (T4 temper) at 400 °C, respectively. In the results, it is shown that the best mechanical properties are obtained by single‐pass liner rolling at 400 °C with a deformation of 60% deformation under the combined effect of grain refinement and precipitation strengthening. The average grain size of the alloy is 7.2 μm and the microhardness is 80 HV. The tensile yield strength, ultimate tensile strength, and elongation at room temperature are 255 MPa, 285 MPa, and 12.7%, which are 14.9%, 15.3%, and 10.4% higher than those of the conventional multi‐pass rolled alloy, respectively.

Tensile properties and microstructural evolution of 17–4 PH stainless steel fabricated by laser hybrid additive manufacturing technology

Wire-based laser directed energy deposition (LDED) technology is an attractive and efficient additive manufacturing technology, which shows great potential in the process of manufacturing high-value engineering components. However, the thermal effect will lead to a large amount of residual tensile stress in the components, and the large crystal structures after solidification seriously affects the tensile performance. The pursuit of high mechanical properties in additive manufacturing components have prompted researchers to seek new strengthening process to produce high-strength components. Therefore, in this paper, laser shock peening (LSP) composite wire-based LDED were used for the additive manufacturing of 17–4 PH stainless steel under the specified experimental conditions, and the effects of LSP on microstructure evolution, microhardness, and tensile properties of wire-based LDED components were systematically studied. Results showed that uniform grains with an average size of 2.31 μm were generated on the top surface of specimen due to the ultra-high plastic strain induced by LSP shock wave. The size of hierarchical martensitic units shows varying degrees of reduction after LSP treatment, which is shown by the width decrease of packet, block and lath. Dynamic recrystallization caused by rearrangement and annihilation of high-density dislocations promoted the grain refinement. Meanwhile, the residual stress was completely converted from tensile state into compressive state with a maximum value of 425 MPa, and the microhardness was also enhanced to a peak value of 432 HV. In addition, we observed that the high-density dislocation environment created by LSP treatment promoted the further precipitation, and the aggregation phenomenon of precipitates was observed in the dense dislocation area. Furthermore, the tensile strength and elongation of LSP treated specimen were improved significantly, which was attributed to the combined effects of grain refinement, introduction of dislocation structures, precipitation strengthening and gradient residual compressive stress. In summary, laser hybrid additive manufacturing technology provides a new idea and method for the production of high-performance precipitation hardening stainless steel components.

Improving the Mechanical Properties of Low‐Carbon Steel by In Situ Strain Aging

A novel continuous process that utilizes the concept of strain aging not only in the automotive industry but also in structural materials as a whole is developed. The principle behind achieving in situ strain aging is as follows. 1) Dislocations are generated through compressive deformation during continuous pressing. 2) The processing conditions at the strain aging temperature create a favorable environment for the diffusion of interstitial atoms, leading to the formation of Cottrell atmospheres. The in situ strain aging‐processed low‐carbon steel demonstrates a significant increase in strength compared to the unprocessed sample (increased yield strength by ≈37.6 MPa), which can be attributed to the strain aging effect, as well as the combined effects of grain refinement and pre‐existing dislocations. Additionally, the generation of dislocations during compressive deformation suppresses void nucleation during pre‐strain, preventing a loss of elongation (reduced uniform elongation by ≈1.5%). The in situ strain aging‐processed low‐carbon steel exhibits a superior strength–elongation combination compared to both the unprocessed low‐carbon steel and strain aging‐simulated counterparts obtained through tensile deformation.

Effect of Repetitive Bending and Straightening Process on Microstructure Properties and Deformation Mechanism of a Ti-Al-Cr-Mo Alloy.

In this research, a repetitive bending and straightening process was carried out on the Ti-3Al-4Cr-Mo alloy for 20 passes. The changes in mechanical properties of the titanium alloy before and after repetitive bending and annealing were studied. The microstructure evolution and deformation mechanism were analyzed. The results show that after the repetitive bending and straightening process, the microstructure of the Ti-3Al-4Cr-Mo alloy is obviously refined, and, simultaneously, the yield strength is significantly improved. After annealing at 850 °C, the plastic ductility of the material was improved. The combined effects of grain refinement and dislocation behavior were the main reasons for the improvement in mechanical properties of the Ti-3Al-4Cr-Mo alloy. Twinning rarely occurred during plastic deformation of the Ti-3Al-4Cr-Mo alloy. The fine grains strongly inhibited the formation of twins. In addition, a small amount of α to β phase transformation was observed during the repetitive bending and straightening process of the material, which may have been induced by strain accumulation.

Effects of multiple laser shock peening impacts on microstructure and wear performance of wire-based laser directed energy deposition 17-4PH stainless steel

As an advanced surface-strengthening technology, laser shock peening (LSP) is suitable for strengthening high-energy beam additive manufacturing components by improving the uneven temperature distribution and mechanical anisotropy problems. The present study investigated the influence of multiple LSP impacts on the microstructure evolution and wear performance of wire-based laser directed energy deposition (LDED) 17-4 PH stainless steel. Results showed that with the increase of LSP impacts, the average grain size of the wire-based LDED layer decreases and the dislocation density increases. Meanwhile, the residual stress was completely converted from tensile state to compressive state, and reaches the maximum value of 424 ± 15 MPa. In addition, the significant improvement of microhardness and wear resistance after 3 LSP impacts is attributed to the combined effects of grain refinement and dislocation strengthening.

The hot deformation behavior, microstructure and texture evolution of homogenized Mg–9Li–1Zn alloy

In this study, the hot deformation behavior, microstructure and texture evolution of Mg–9Li–1Zn (LZ91) alloy were investigated systematically, and the best Arrhenius hot deformation constitutive equation model and processing map of the LZ91 alloy were developed. Hot compression tests were performed at deformation temperatures and strain rates ranging from 175 °C to 275 °C and 0.001 s−1 to 1 s−1, respectively. The results showed that Arrhenius constitutive equation can predict accurately the hot deformation behavior of LZ91 alloy. The instability areas for this alloy were concentrated in the range of 175 °C–220 °C, 0.01 s−1–0.1 s−1 and 225 °C–260 °C, 0.001 s−1–0.002 s−1 and 0.02 s−1–1 s−1. The observation of microstructure revealed that the alloy is deformed by the cooperation of the basal slip system and the pyramidal conical slip system. In addition, the hardness which increases in a gradient from the center to the edges is the result of the combined effect of grain refinement and texture.

Effect of initial orientation on microstructure and mechanical properties of AZ31 Mg alloy sheets via accumulated extrusion bonding

In this study, effects of initial orientation on microstructure evolution and mechanical properties of AZ31 Mg alloy sheets via accumulated extrusion bonding (AEB) was systematically studied. The samples with RD and TD parallel to extrusion direction (ED) were labeled as RED and TED, respectively. RD and TD pieces alternately stacked was named as RTED. The results revealed that under three-dimensional compressive stress, {10-12} tensile twinning dominated the first stage deformation in container. As the plunger continuous press down, dynamic recrystallization (DRX) occurred, and the newly fine DRXed grains along original and twin grain boundaries gradually consumed the matrix and twin grains. The microstructure was completely transformed into recrystallized grain structure at sizing band with an average grain size of ∼0.9 ​μm in TED sample, smaller than that of RED sample. After the alloys extruded out of the die, DRXed grains significantly grew to ∼4.5 ​μm and 3.5 ​μm for RED and TED samples, respectively. A laminated microstructure was obtained with average grain sizes of∼4.4 ​μm in RD layers and 3.5 ​μm in TD layers for RTED sample. The AEB processed samples exhibited an ED-tilt double-peak basal texture with similar texture intensity. The tensile tests results indicated that attributed to the combined effect of grain refinement and texture evolution, the yield strength and fracture elongation of RED and TED samples was significantly improved. The heterogeneous microstructure in RTED sample induced an extra work hardening (HDI-work hardening) in tensile deformation and resulted in a further improved elongation of 32.0%.

Influence of ECAP process on mechanical, corrosion and bacterial properties of Zn-2Ag alloy for wound closure devices

Actual polymeric wound closure devices are not optimal for load-bearing applications due to the low mechanical properties and the risk of inflammation and bacterial infection mainly produced by multifilament and braided configurations. Biodegradable metallic Zn alloys are promising materials candidates; however, mechanical performance, corrosion behaviour, and biological response should be controlled in order to inhibit the risk of inflammation and bacterial infection. To this end, a Zn-2Ag (2 wt% Ag) alloy was processed by ECAP to evaluate the concurrent combined effect of grain refinement and Ag alloying on biodegradation and antibacterial activity. Two ECAP cycles were successfully applied to a Zn-2Ag alloy obtaining a homogeneous ultra-fine-grained structure in which nanoindentation maps suggested isotropic mechanical properties. Lower UTS and YS with higher elongation was reported after ECAP with similar corrosion rates as before processing. ECAP processed samples showed a homogeneous Ag+ release below the minimum inhibitory concentration for S. Aureus and no antibacterial effect was observed by diffusion. As expected, the presence of Ag in Zn-Ag alloys reduced bacterial attachment. Nevertheless, ECAP processed Zn-2Ag provided an excellent antibacterial activity after 3 h probably caused by the uniformly degraded and thus, non– stable, surface observed after bacterial adhesion.

Effects of supersonic fine particle bombardment on the microstructure and corrosion properties of Ti-6Al-3Nb-2Zr-1Mo alloy

The surface of Ti-6Al-3Nb-2Zr-1Mo (Ti80) alloy was treated with supersonic fine particle bombardment (SFPB) for different time durations from 30 s to 90 s. The effects of different SFPB time on the microstructure and corrosion properties of the specimens were systematically investigated. The surface grains of the specimens with different SFPB treatment time were all refined and formed surface nanostructures, and the surface microhardness increased by 23.9 %, 31.8 % and 39.6 %, respectively, compared with the untreated specimens. After SFPB, compressive residual stress (CRS) was generated in the specimens, with maximum CRS of Ti80 alloy specimens at different SFPB time were −423 MPa, −451 MPa and −487 MPa, respectively. The results of electrochemical and immersion experiments showed that the corrosion rate of SFPB-treated specimens was reduced, and the passivation effect was best at 60 s of SFPB treatment and decreased with the increase of SFPB treatment time. The SFPB treatment improved the corrosion resistance of the specimens, which was the result of the combined effect of grain refinement and surface CRS.

Comparison of CoCrFeNi coatings prepared via high-speed laser cladding and normal laser cladding on microstructure and properties

Two kinds of CoCrFeNi high entropy alloy coatings were prepared by normal laser cladding (N-) and high-speed laser cladding (HS-), respectively. The comparative analyses of crystallographic orientation distribution, microstructure, microhardness, wear resistance and corrosion resistance of both coatings were conducted. The results show that the phase structures of HS-CoCrFeNi and N–CoCrFeNi coatings are single FCC solid solutions. The dendrite size of HS-CoCrFeNi coating is only half of that of N–CoCrFeNi coating. The microhardness of HS-CoCrFeNi coating (380 HV0.2) is about 2.3 times that of N–CoCrFeNi coating (165 HV0.2), due to the combined effect of grain refinement, dispersion strengthening and dislocation strengthening. The wear resistance and corrosion resistance of HS-CoCrFeNi coating are better than N–CoCrFeNi coating. With the increase of friction speed, the same wear mechanism of the two coatings is obtained, changing from abrasive wear to adhesive wear and fatigue wear. High-speed laser cladding is a promising technology to promote the development and application of high entropy alloys in the industry.

Effect of Geometrical Parameters of Microscale Particles on Particle-Stimulated Nucleation and Recrystallization Texture of Al-Si-Mg-Cu-Based Alloy Sheets.

The effects of the shapes (needle and round) and volume fractions (low and high) of microscale particles in Al-Si-Mg-Cu-based alloys on recrystallization behavior, texture evolution, mechanical properties, and formability are investigated. The recrystallized grain size decreases as the size and volume fraction of the particles decrease and increase, respectively, regardless of the particle shape. The investigated alloys with a relatively low volume fraction of 0.7 to 2.4 vol.% exhibit higher efficiency particle-stimulated nucleation (PSN) than alloys with a high volume fraction of 6.0 to 21.0 vol.%. This is because the interaction between the particles and dislocations cannot be greatly promoted when the volume fraction of the particles is large enough to form agglomerates. The sheets with round-shaped particles exhibit higher yield strength (YS) and elongation (EL) than sheets with needle-shaped particles. The improvement in YS is due to the combined effects of grain refinement and particle strengthening, and the EL is improved by reducing the probability of cracking at the tips of round-shaped particles. The sheets with round-shaped particles exhibit relatively higher average plastic strain ratio (r¯) and planar anisotropy (∆r) than the sheets with needle-shaped particles, owing to the development of Goss {110}&lt;001&gt; or rotated-Goss {110}&lt;110&gt; orientations.

Mechanical response of high purity Zn wires with different diameters

• Different Zn wires with diameters of 0.3, 0.5, 1.0, 4.0, and 6.0 mm were prepared. • The highest ultimate tensile strength (144.6 MPa) occurred for diameter of 0.3 mm. • Smallest grain size (4.71 μm for diameter of 6.0 mm) delivered 120% fracture strain. • Tensile deformation relies on combined effects of grain refinement, LAGBs, and twins. The high purity Zn wires with different diameters (i.e. 0.3, 0.5, 1.0, 4.0, and 6.0 mm) were prepared through extrusion and/or cold drawing. Then, mechanical response was investigated via sophisticated tensile tests, followed by materials characterization. Tensile deformation shows that grain refinement played a significant role in the Zn wires with diameters of 4.0 and 6.0 mm. Regarding the Zn wires with 0.3, 0.5, and 1.0 mm in diameter, the corresponding tensile properties (i.e. strength and ductility) were mainly attributed to the synergism of grain refinement, low-angle grain boundaries, and twins.

Synchronous-hammer-forging-assisted laser directed energy deposition additive manufacturing of high-performance 316L samples

Plastic-deformation-assisted method has positive effect on regulating microstructure and mechanical properties of additive manufacturing (AM) metal samples. However, when fabricating weakly rigid metal samples by laser directed energy deposition (LDED), there are great limitations in the applicability and process flexibility of the commonly used rolling deformation auxiliary methods, which needs to be further improved. In this study, a synchronous-hammer-forging-assisted laser directed energy deposition (SHLDED) method is developed, and the effect of synchronous-hammer-forging on the microstructure and mechanical properties of LDED-processed 316L stainless steel samples is investigated. The results show that large plastic deformation up to 21 % of deposited materials can be achieved using a small hammering force of 55 N. Compared with LDED sample, the microstructure of SHLDED sample shows obvious equiaxed grains and refinement effect. The maximum intensity of the pole figure decreases by 50 % and the average grain size decreases by 69 %. Owing to the combined effect of grain refinement and work hardening, the yield strength (YS), ultimate tensile strength (UTS), and microhardness of SHLDED sample reach 494 ± 19 MPa, 677 ± 7 MPa, and 243 ± 11 HV 0.2 , respectively, which are 41 %, 10 %, and 22 % higher than those of LDED sample. This study provides a new method for microstructure and mechanical properties regulation of LDED metal samples. • A synchronous-hammer-forging-assisted LDED device was developed. • 21 % large plastic deformation was achieved using small hammering force of 55 N. • The microstructure achieved 69 % grain refinement and 50 % anisotropy reduction. • The yield strength and tensile strength were improved by 41 % and 10 % respectively.

Novel Mg-Bi-Mn wrought alloys: The effects of extrusion temperature and Mn addition on their microstructures and mechanical properties

Designing and developing the Mg alloys with low cost and high performance is of the great significance. Novel Mg-1Bi- x Mn ( x = 0, 1 and 2 wt.%) extruded alloys, in this work, were fabricated at different extrusion temperatures (220, 250 and 300 °C). The effects of extrusion temperature and Mn addition on the microstructures and mechanical properties of extruded alloys at room temperature were investigated. The results showed that decreasing the extrusion temperature could refine the average grain size, weaken the basal fiber texture intensity and improve the microstructural homogeneity of extruded alloys. When the Mn element was added to the Mg-1Bi alloy, the average grain size further reduced. Simultaneously, the number fraction of low angle grain boundaries (LAGBs) increased, along with the occurrence of regions without dynamic recrystallization (unDRX). The combined effects of grain refinement and coarse unDRXed structure made the textures of the extruded Mg-1Bi- x Mn alloys never obviously change. Besides few large size un-dissolved second phases, fine Mg 3 Bi 2 and α-Mn phases were precipitated in the extruded Mg-1Bi- x Mn alloys and partial nano-scale α-Mn particles pined at grain boundaries (GBs) to effectively impede the migration of GBs for grain refinement. Microstructural variations determined the extruded Mg-1Bi-2Mn alloy to exhibit the highest yield strength of ∼ 319.2 MPa with the appropriate elongation-to-failure of ∼ 13% at the extrusion temperature of 220 °C, and they enabled the extruded Mg-1Bi-1Mn alloy to show the highest elongation-to-failure of ∼ 26% without the obvious loss of yield strength of ∼ 252.1 MPa.

Enhanced Strength and Hardness of AS41 Magnesium Alloy Fabricated by Selective Laser Melting

AS41 magnesium alloy possesses outstanding performance features such as light weight, high strength to toughness ratio and excellent heat resistance due to the addition of Si element, while traditional casting methods are prone to inducing large grain size and coarse Mg2Si phase. In this study, we first reported utilizing the selective laser melting (SLM) technique, fabricating AS41 samples and exploring the effect of laser energy densities on the metallurgical quality by characterizing and investigating the microstructure and mechanical properties. Results showed that the optimal laser energy density range was 60 to 100 J/mm3. Average grain size of only 2.9 μm was obtained with weak texture strength of 1.65 in {0001} orientation. Meanwhile, many dispersed secondary β-Mg17Al12 and Mg2Si phases were distributed inside the α-Mg matrix. It was confirmed that the SLM process introduced more grain recrystallization, inducing giant high-angle grain boundaries (HAGBs) and hindering the movement of dislocations, therefore forming dislocation strengthening while achieving grain refinement strengthening. Finally, three times the ultimate tensile strength of 313.7 MPa and higher microhardness of 96.4 HV than those of the as-cast state were obtained, verifying that the combined effect of grain refinement, solid solution strengthening and precipitation strengthening was responsible for the increased strength. This work provides new insight and a new approach to preparing AS41 magnesium alloy.