Re-melted Zone Research Articles

Formation Mechanism of Stray Grain in Laser Remelting Zone of DD6 Nickel‑Based Single Crystal Superalloy

Formation Mechanism of Stray Grain in Laser Remelting Zone of DD6 Nickel‑Based Single Crystal Superalloy

Microstructure evolution and fracture behavior of Ti–6Al–4V fabricated by WAAM-LDM additive manufacturing

WAAM and LDM are two typical DED technologies. WAAM-LDM additive manufacturing technology can achieve the purpose of producing large and complex Ti–6Al–4V components, improving processing efficiency and precision. However, there is a lack of in-depth research on the microstructure evolution mechanism and the fracture behavior of WAAM-LDM samples. Therefore, horizontal and vertical WAAM samples were invoked as the substrate for LDM processes in this study, and the mechanical properties and tensile fracture behavior under different load directions were evaluated. The results show that the samples fabricated by WAAM-LDM manufacturing consist of four zones: WAAM zone, heat affected zone (HAZ), remelting zone (RZ) and LDM zone. WAAM zone mainly composed of coarse colony structure, HAZ and RZ are dominated by α colonies and fine basketweave structure, respectively, and LDM zone consists of acicular α phases and fine basketweave structure. The thickness of α laths shows a trend of ‘WAAM > HAZ > LDM > RZ’. The strengths are greatly improved at the interfaces due to the good metallurgical bonding and finer microstructure. All the fractures locate at WAAM zone during tensile test and propagate along the basketweave structure. These strengths of WAAM-LDM samples under the action of horizontal loading are higher than that of WAAM samples, and all the elongations of WAAM-LDM samples are higher than 10 %.

Microstructure distribution characteristics of LMD-WAAM hybrid manufacturing Ti-6Al-4V alloy

Laser melting deposition (LMD) and Wire arc additive manufacturing (WAAM) are representative metal additive manufacturing (AM) technologies. To explore the feasibility of using the LMD-WAAM hybrid process to fabricate large and complex components, a preliminary investigation of Ti6Al4V was conducted. In this study, a WAAMed sample was used as a substrate for the LMD process at different laser powers. The effects of laser power on the grain evolution and mechanical properties of the Ti6Al4V alloy were studied. The results indicated that different thermal histories formed a graded microstructure from the LMD to the WAAM zones. The Electron backscatter diffraction texture intensity of the α phase gradually increased from the remelting zone (RZ) to the top-LMD zone and from the WAAM zone to the heat-affected zone. In the LMD zone, the length of the acicular α decreased and the lamellar α content increased with increasing laser power. Ductile fracture characteristics were apparent with few cleavage fractures and pore defects, which led to different fracture locations. Further, the microhardness of the interface zone exhibited a peak because the microstructure of the RZ was fine, leading to a higher microhardness.

Microstructures and wear resistance of Zr-4 and N36 alloys subjected to pulsed laser surface remelting

Two typical Zr alloys (Zr-4 and N36) for nuclear applications were surface-treated by laser surface remelting (LSR). Electron channeling contrast imaging and electron backscatter diffraction were used to characterize their main microstructure characteristics before and after the LSR, which were also correlated with their hardness and wear resistance. The results show that two surface modification zones with distinct microstructure characteristics appear in both the LSRed Zr alloys: (i) remelting zone (RZ) composed of fine α laths with dense internal nano-twins, and (ii) heat affected zone (HAZ) consisting of blocky α, lath α and second phase particles. The average hardness values of the RZs of Zr-4 and N36 alloys are 254.9 ± 8.5 HV and 269.5 ± 7.9 HV, respectively, ∼30% higher than their substrates. The wear rates of the LSRed Zr-4 and N36 alloys are found to be about 30% and 18% lower than their substrates, respectively, indicating significantly improved wear resistance. Comprehensive analyses reveal that refined grains, solid solution and internal nano-twins generated by ultrafast heating and cooling during the laser treatment have jointly led to the enhanced surface hardness of the LSRed Zr alloys, accounting for their improved wear resistance as well. Compared to the Zr-4 alloy, the refinement of the surface microstructure of the N36 alloy after the LSR treatment is more remarkable, contributing to higher hardness and wear resistance, which is mainly related to the addition of 1 wt.% Nb.

Additive manufacturing of Ti-Al functionally graded material by laser based directed energy deposition

PurposeTi-Al composite plates have been used in aerospace and other important fields for specific purposes in recent years. However, relatively few studies have concentrated on Ti-Al additive manufacturing because during additive manufacturing process the local fusion and mixing of Ti/Al are inevitable. These areas where Ti and Al are mixed locally, especially interface, could easily generate high residual stresses and cracks. This study aims to manufacture Ti-Al functionally graded material and investigate the interaction of interface.Design/methodology/approachIn this study, Ti6Al4V/AlSi10Mg functionally graded materials were fabricated by laser based directed energy deposition (L-DED) and a strategy using V interlayer to relieve interfacial stress was investigated.FindingsThe area between the two materials was divided into transition zone (TZ) and remelting zone (RZ). The phase distribution, microstructure and micro-Vickers hardness of the TZ and RZ were investigated. Typical intermetallic compounds (IMCs) such as TiAl3, Ti3Al and Ti5Si3 were found in both composites. The addition of V interlayer promoted the homogenization of IMCs near interface and led to the formation of new phases like V5Si3 and Al3V.Originality/valueThe solidification process near the interface of Ti-Al functionally graded material and the possible generation of different phases were described. The result of this paper proved the feasibility of manufacturing Ti-Al functionally graded material by L-DED.

Multiscale plasticity behavior and fatigue performance of laser melting multi-layer nickel-based superalloys upon heat treatments

The present work focuses on heat treatment effects on cyclic plasticity behavior, multiscale strengthening mechanisms and low cycle fatigue performance of laser melting nickel-based superalloys. Microscopic indentation analysis, mesoscopic DIC analysis and macroscopic material testing were conducted to identify multiscale mechanical properties. A DIC-aided indentation method was developed to identify the constitutive parameters of the laser melting material by introducing the reference material. The dendritic–cellular microstructures in the remelting zone (RZ) significantly decrease the effects of the grain size and morphology. Heat treatments can improve the strength but decrease the ductility of RZ and do not affect the macroscopic stress–strain responses of the multilayered material. Moreover, the strengthening mechanisms in the laser melting material were verified to reveal size- and plasticity-dependent effects. The strengthening contributed by grain boundaries and twin boundaries yields little effect on the strength at micro scales and the influences increase with plastic deformations. Furthermore, the aging treatment increases the fatigue life of RZ by factor 2 and, however, decreases the low cycle fatigue performance of the multilayered material, meaning that the under-matched material can be stronger than the base material in certain configurations. The stabilized fatigue load of the laser melting material has strong correlations with the mismatching and loading levels. The present study provides a deep insight into the strengthening mechanisms and cyclic plasticity behaviors of laser-manufactured materials.

Effects of heat treatments on microstructure and mechanical properties of laser melting multi-layer materials

The effects of different heat treatments on the microstructure and mechanical properties of the laser melting nickel-based superalloys were systematically investigated. The strength improvement of the heat-treated material was mainly derived from the aging treatment, which converted the γ matrix together with Niobium to the strengthening phases γ′′ and γ′. The solution treatment dissolved partial Laves phases to form the short-acicular δ phases in the remelting zone (RZ), whereas the homogenization treatment dissolved most precipitates including the Laves phase and δ phase, leading to significant grain coarsening in the multi-layer material. Moreover, based on the instrumented indentation reverse analysis, RZ shows consistent stress–strain relationships after the heat treatments, reaching the same level as the heat-treated base material (BM). The remelting-affected zone (RAZ) reveals more outstanding mechanical properties after the direct aging (DA) treatment for the work hardening contributed by dislocation strengthening. Additionally, the residual stresses and deformations in RAZ provide an extra thermodynamic driving force for the grain recrystallization and the formation of the short-clavate δ phase in the solution-treated RAZ. The remaining large grains and small Taylor factor in RZ are considered to lead to a reduction of the mesoscopic yield strength, which cannot be identified in microscopic indentation analysis. The DA heat treatment is recommended for the strength improvement of the laser melting materials.

Multi-scale investigation of A356 alloy with trace Ce addition processed by laser surface remelting

Laser surface remelting (LSR) has shown great application potential in Al-Si alloy parts (e.g., surface strengthening, surface repairing). However, the microstructural details and properties of LSR-treated hypoeutectic Al-Si alloy remains to be investigated. In this work, the microstructure of an Al-7Si alloy with adding 0.05 wt% Ce fabricated by LSR was studied through multi-scale characterization. Three regions with distinct morphologies after LSR were obtained: i) the remelting zone (RMZ) including an equiaxed grain region and a columnar to equiaxed transition (CET) region; ii) the heat-affected zone (HAZ) with segregation of Si; iii) substrate zone (SZ). Nanoscale eutectic Si particles were observed in RMZ and HAZ. Moreover, it is confirmed for the first time that the Ce atom can absorb on the {111}Si planes and leads to high density of twins and stacking faults. After LSR, the increased microhardness of RMZ is mainly attributed to the precipitation and dislocation strengthening. By further T6 heat treatment, the microhardness of RMZ increases to 126 HV. Dispersed small Si particles decrease the critical stress of crack propagation. Additionally, the high density of twins, stacking faults and Al-rich clusters within Si particle plays a significant role in toughness improvement.

Improving mechanical properties of welds through tailoring microstructure characteristics and fracture mechanism in multi-pulse resistance spot welding of Q&P980 steel

In the present research, the multi-pulse resistance spot welding involving three thermal cycles has been carried out on the Q&P980 steel sheet with the thickness of 1.8 mm. The influence of welding pulses on the microstructure evolution and mechanical properties of the welded specimens was analyzed through EPMA, SEM, TEM and tensile test, etc. It is found that there is a crack sensitive area in single and double-pulse samples, which is corresponding to the broadening of the partially melted zone with severe element segregation. Furthermore, the softened of nugget associated with microstructure coarsening on the outside of the re-melting zone can be observed during multi-pulse welding. As the nugget size increases, the enlarged connection/joint area between the sheets significantly enhances the ability of the nugget to resist tensile shear stress, leading to the increase of tensile-shear strength. Due to the crack propagating away from the partially melted zone into the softened nugget, where the tempered martensite provides a higher resistance to crack initiation and propagation, the cross-tension properties have been improved by applying the tempering pulse with low-level current. The multi-pulse welding samples show a better combination of tensile-shear and cross-tension properties, i.e. their peak load of cross tension (13.19 kN) is increased by 160% and 56% respectively, while the energy absorption (108.49 J) is raised by 390% and 107% respectively, compared with the single and double pulse samples.

The micro-zones formation of Zr-based bulk metallic glass composite fabricated by laser 3D printing

In this study, a Zr-based bulk metallic glass composite (BMGC) was successfully fabricated by laser 3D printing with pre-laid powders. The results showed that the printed bulk metallic glass composite was composed primarily (82.5 vol%) of amorphous phase along with a small fraction of intermetallic compounds. The crystallization characteristics of different micro-zones in the as-printed BMGC were studied. It was found that the molten pool had a fully amorphous structure, while some nanocrystals were found in the re-melted zone, and both dendrites and nanocrystals were observed in the heat affected zone (HAZ). The nanoindentation results showed that the HAZ had the highest hardness, elastic modulus, and elastic recovery compared with the re-melted zone and molten pool zone. The forming mechanism of bulk metallic glasses composite was further studied by finite element analysis of the heating and cooling processes in laser 3D printing.

Effects of pulsed laser surface remelting on microstructure, hardness and lead-bismuth corrosion behavior of a ferrite/martensitic steel

A typical ferritic/martensitic (F/M) steel sheet was subjected to pulsed laser surface remelting (LSR) and corrosion test in lead-bismuth eutectic (LBE) at 550 °C. There present two modification zones with distinct microstructures in the LSRed specimen: (1) remelted zone (RZ) consisting of both bulk δ-ferrite grains and martensitic plates and (2) heat-affected zone (HAZ) below the RZ, mainly composed of martensitic plates and high-density precipitates. Martensitic transformation occurs in both the RZ and the HAZ with the Kurdjumov-Sachs and Nishiyama-Wassermann orientation relationships followed concurrently, resulting in scattered orientations and specific misorientation characteristics. Hardnesses of the RZ and the HAZ are 364 ± 7 HV and 451 ± 15 HV, respectively, considerably higher than that of the matrix (267 ± 3 HV). In oxygen-saturated and oxygen-depleted LBE, thicknesses of oxide layers developed on both the as-received and the LSRed specimens increase with prolonging corrosion time (oxide layers always thinner under the oxygen-depleted condition). The corrosion resistance of the LSRed F/M steel in oxygen-saturated LBE is improved, which can be attributed to the grain-refinement accelerated formation of dense Fe–Cr spinel. In oxygen-depleted LBE, the growth of oxide layers is very low with both types of specimens showing similar corrosion resistance.

Microstructure and Properties of the Aluminum Alloyed with ZrO Powder Using Fiber Laser

The scope of the work covers the development of the relationship between the chemical composition of surface-modified aluminium and its mechanical properties. This article presents the impact of laser alloying with ZrO powder on the microstructure and mechanical properties of pure aluminium. In order to study the phenomena occurring during the laser alloying process, microstructural studies were carried out using optical microscopy. Additionally, the properties of the obtained alloy were tested - abrasion resistance and hardness measured at low load force. As a result of the alloying process, three distinct zones were identified: the remelting zone (RZ), the diffusion zone (DZ) and the heat affected zone (HAZ). The surface modification resulting from laser alloying increases the hardness and abrasion resistance of the material.

New Ti–35Nb–7Zr–5Ta Alloy Manufacturing by Electron Beam Melting for Medical Application Followed by High Current Pulsed Electron Beam Treatment

High-current pulsed electron-beam (PEB) treatment was applied as a surface finishing procedure for Ti–35Nb–7Zr–5Ta (TNZT) alloy produced by electron beam melting (EBM). According to the XRD results the TNZT alloy samples before and after the PEB treatment have shown mainly the single body-centered cubic (bcc) β-phase microstructures. The crystallite size, dislocation density, and microstrain remain unchanged after the PEB treatment. The investigation of the texture coefficient at the different grazing angle revealed the evolution of the crystallite orientations at the re-melted zone formed at the top of the bulk samples after the PEB treatment. The top-view SEM micrographs of the TNZT samples treated by PEB exhibited the bcc β-phase grains with an average size of ~85 μm. TEM analysis of as-manufactured TNZT alloy revealed the presence of the equiaxed β-grains with the fine dispersion of nanocrystalline α and NbTi4 phases together with β-Ti twins. Meanwhile, the β phase regions free of α phase precipitation are observed in the microstructure after the PEB irradiation. Nanoindentation tests revealed that the surface mechanical properties of the melted zone were slightly improved. However, the elastic modulus and microhardness in the heat-affected zone and the deeper regions of the sample were not changed after the treatment. Moreover, the TNZT alloy in the bulk region manufactured by EBM displayed no significant change in the corrosion resistance after the PEB treatment. Hence, it can be concluded that the PEB irradiation is a viable approach to improve the surface topography of EBM-manufactured TNZT alloy, while the most important mechanical parameters remain unchanged.

Investigation on the peak temperature and surface defects on the carbon steel treated by rotating CW laser

A newly developed rotating continuous-wave laser equipment was adopted as an alternative laser-based surface cleaning method. To evaluate the thermal effects of laser cleaning on base material, a modified calculation method for laser-induced peak temperature distribution considering overlapping effects was proposed. Various laser-processing parameters were adopted to irradiate carbon steel plates. The re-melted zone (MZ) of laser-treated specimens was observed under optical microscopy and used to verify the calculation method. Surface morphologies and roughness of laser-treated specimens were also investigated. The results showed that the peak temperature distribution obtained from the modified calculation method properly describes the MZ depth in laser-treated specimens. Investigation on laser-treated specimens revealed that results of laser heat effects improved in rougher surface conditions, and that frequent overlapping of laser beam can induce surface defects. The modified calculation method could help to optimize laser processing parameters to reduce melting of base material and avoid surface defects.

Laser Surface Alloying of Austenitic 316L Steel with Boron and Some Metallic Elements: Microstructure.

Austenitic 316L steel is known for its good oxidation resistance and corrosion behavior. However, the poor wear protection is its substantial disadvantage. In this study, laser surface alloying with boron and some metallic elements was used in order to form the surface layers of improved wear behavior. The microstructure was studied using OM, SEM, XRD, and EDS techniques. The laser-alloyed layers consisted of the only re-melted zone (MZ). The hard ceramic phases (Fe2B, Cr2B, Ni2B, or Ni3B borides) occurred in a soft austenitic matrix. The relatively high overlapping (86%) resulted in a uniform thickness and homogeneous microstructure of the layers. All the laser-alloyed layers were free from defects, such as microcracks or gas pores, due to the use of relatively high dilution ratios (above 0.37). The heat-affected zone (HAZ) wasn’t visible in the microstructure because of the extended stability of austenite up to room temperature and no possibility to change this structure during fast cooling. The use of the mixtures of boron and selected metallic elements as the alloying materials caused the diminished laser beam power in order to obtain the layers of acceptable quality. The thickness of laser-alloyed layers (308–432 μm) was significantly higher than that produced using diffusion boriding techniques.

The Effect of Temperature Distribution during Laser Heat Treatment of Gas-Nitrided 42CrMo4 Steel on the Microstructure and Mechanical Properties

A gas-nitrided layer was produced on the toughened 42CrMo4 low-alloy steel using the changeable nitriding potential in order to limit the thickness of a brittle ε zone. The microstructure consisted of the compound ε + (ε + γ’) zone and diffusion zone (nitric sorbite with γ’ precipitates). Such a layer was subjected to laser heat treatment with or without remelting. The single laser tracks were formed using various laser beam powers (in the range of 0.234–0.624 kW) and scanning rates (in the range of 2.24–3.84 m·min−1) and the same laser beam diameter (2 mm). The microstructure of laser-modified nitrided layer usually consisted of re-melted zone (MZ) with coarse-grained nitric martensite Feα’ and possible ε precipitates, heat-affected zone (HAZ) with fine-grained nitric martensite Feα’ and γ’ precipitates and diffusion zone with nitric sorbite and γ’ precipitates. Sometimes, the compound zone was partially re-melted and an amount of iron nitrides remained in the MZ. Only one laser track was characterized by the different microstructure, consisting of the compound ε + (ε + γ’) zone, HAZ with fine-grained nitric martensite Feα’ and γ’ precipitates and diffusion zone with nitric sorbite and γ’ precipitates. This laser track was formed without visible effects of remelting. The effect of temperature distribution during laser heat treatment of gas-nitrided 42CrMo4 steel on the microstructure and mechanical properties was studied. The equations developed by Ashby and Esterling were used in order to determine the temperature distribution along the axis of each laser track. Taking into account the temperature profiles, it was possible to calculate the depths of MZ and HAZ. These predicted values were compared to those-measured based on the microstructure observations, obtaining good compatibility. The microstructure of the produced surface layers influenced the mechanical properties such as hardness and Young’s modulus. The hardness of MZ was higher than that of ε zone and lower than that of ε + γ’ zone when compared to nitrided layer. Whereas Young’s modulus of MZ was significantly higher than those characteristic of the compound zone in gas-nitrided layer (both ε and ε + γ’ zone) and similar to that of HAZ. The laser heat treatment (LHT) without remelting resulted in the similar hardness and slightly higher Young’s modulus of ε zone in comparison with the nitrided layer. Simultaneously, such a treatment of the nitrided layer did not influence the hardness and the Young’s modulus of ε + γ’ zone considerably. The hardness of HAZ was higher than that of MZ and that of the same area of diffusion zone in the nitrided layer because of the presence of fine-grained nitric martensite with γ’ precipitates after laser quenching.

Heterogeneous microstructure and voids dependence of tensile deformation in a selective laser melted AlSi10Mg alloy

Microstructure and voids evolution of a selective laser melted (SLM) AlSi10Mg alloy during tension were systematically investigated. The SLM AlSi10Mg sample is featured with a multi-level heterogeneous microstructure that is composed of melt pools (MPs), columnar Al grains and sub-cells. According to the Si morphologies and thermal history, the MP could be divided into three regions, including the fine structure zone (FSZ), remelted zone (RMZ) and heat-affected zone (HAZ), respectively. The Si segregation phenomenon on sub-cells boundaries is observed and may attributed to the constitutional supercooling. The tensile deformation behaviors of the vertical sample (V-sample) vary from the horizontal sample (H-sample) for that heterogeneous microstructure arises strain localization in V-sample. In addition, the voids have no obvious effect on the uniform plastic deformation, while they may affect the non-uniform deformation during tension. The combined effects of strain localization and void contribute to the earlier break in V-samples than in H-samples.

The Crystallization Mechanism of Zr-Based Bulk Metallic Glass during Electron Beam Remelting.

Bulk metallic glasses (BMGs) are promising for multifunctional and structural application in different industries. However, the limited size of BMGs hinders their further application. The welding of BMGs has shown the possibility of getting rid of the casting size limitation. The heat-affected zone (HAZ) and fusion zone (FZ) often undergo severe crystallization during the welding process. It is still unclear whether the crystallization occurs during the heating process or the cooling process. To figure out the crystallization mechanisms of Zr-based BMGs during the electron beam welding process, the Zr-based BMGs with the composition of Zr41.2Ti13.8Cu12.5Ni10Be22.5 were remelted by electron beam. The microstructures of the HAZ and the remelting zone (RZ) were analyzed. The thermal field of the electron beam welding was obtained by the finite element method (FEM). The critical conditions for crystallization during the heating and cooling processes were obtained by differential scanning calorimetry (DSC) and the Kissinger equation. The results show that the Zr41.2Ti13.8Cu12.5Ni10Be22.5 in the HAZ undergoes severe crystallization, while the Zr41.2Ti13.8Cu12.5Ni10Be22.5 in RZ keeps amorphous state after the remelting process. The low cooling rate in the HAZ is responsible for its crystallization.

Study on microstructure and tensile properties of 316L stainless steel fabricated by CMT wire and arc additive manufacturing

An austenitic stainless steel 316L part was fabricated by cold metal transfer wire and arc additive manufacturing (CMT-WAAM), and its microstructure, microhardness and tensile properties were investigated. Results showed that the as-built 316L part exhibited a multilayered structure along the building direction. In the transverse direction (perpendicular to scanning direction) of each layer, there was also a multilayered structure of alternating overlapping zone (OA) and re-melting zone (RA). Compared with the OA, the RA had higher ferrite content, smaller austenite dendrite size, more dispersed orientation and lower residual stress. The overall multilayered structure and the intra-layer non-equilibrium microstructure exhibit a great influence on the mechanical properties of as-built 316L part. Along the building and transverse direction, the microhardness distribution in the OA was uniform, while the RA showed a trend of lower hardness in the middle and higher hardness on both sides of the RA layer. The effect of multilayered structure on tensile properties was stronger in the transverse direction than that in the building direction. The deformation feature was obviously inconsistent between the OA and RA. Local necking and fracture always occurred in the OA. Microvoids trended to initiate at silicate impurity particles, grow into large cracks, and finally lead to material failure during tension.

Surface Properties Enhancement of Light Alloys by Appliance of Laser Treatment

Laser surface treatment is at present one of up-to-date methods for surface layer engineering, in this technique into the matrix material are introduced some amount of alloying additives. So the surface layer is obtained in form of composite material consisting of ceramic particle powders with different properties influencing the surface layer appliance possibilities. Using the technology it is possible to obtain a layer revealing a structured structure consisting of the heat affected zone (HAZ), transition zone (TZ) and remelted zone (RZ), as well as the substrate material. The laser is without cracks and defects as well as has with a slightly higher hardness value compared to the raw substrate material. The used laser power range is set in the range between 1.0 to 2.5 Kw, with the laser scan rate of the beam head in a range between 0.25-0.75 m/min, depending of the applied laser power and material used for alloying.This study was conducted to determine the effect of carbide on oxide ceramic powders addition on the microstructure and mechanical properties their changes and enhancement possibilities during a rapid solidification process of the remelted surface layer. The investigation should help to use this laser treatment technology for alloying of ceramic powder particles into the surface of light alloys, especially magnesium and aluminium. The scientific reason of this work is the usage of High Power Diode Laser (HPDL) for improvement of aluminium`s mechanical properties, especially the surface hardness and war resistance.There was found during the investigations and analysis of the results that, the obtained surface layer is without cracks and defects as well as with a relatively higher hardness compared to the raw material, after standard heat treatment. The hardness value increases according to the laser power used so that the highest power applied gives the highest hardness value in the remelted layer, similar relation can be found in the wear resistance parameters, which increases also with increasing laser power.The findings of the investigations allows to state, that the distribution of the used ceramic particles is generally satisfied, especially the carbide powder was confirmed in the alloys matrix, the particles are mainly present in the upper part of the surface layer or in the bottom zone of the remelted area. The hardness value increases in general according to the laser power used and the highest power results with the highest hardness value in the surface layer. The main aim of this work is to investigate and determine the effect of HPDL remelting and alloying on the cast Al-Si-Cu and Mg-Al-Cu cast aluminium and cast magnesium alloys micro structure for possible application in real working conditions mainly for light metal constructions as well as in many branches of the industry like automotive and rail transportation.