Avrami Exponent Research Articles

Short-range order patterns in Mg66Zn29Ca5 metallic glass: Phase transformations and crystallization kinetics

Thanks to outstanding mechanical and chemical properties, metallic glasses have been recently alluring for biomedical applications. However, inadequate knowledge of atomic rearrangements as well as kinetics and mechanisms of crystallization prevents further microstructure improvement controlling the properties. In this work, we reveal that hierarchical transformations happen during the crystallization of Mg66Zn29Ca5 metallic glass ribbons which were investigated using differential scanning calorimetry (DSC), electron microscopy (SEM and TEM), and X-ray diffraction (XRD). The activation energies corresponding to the crystallization of the glassy ribbons were evaluated by different thermodynamic models, i.e., Kissinger, and Augis and Bennett analysis. Our findings prove the formation of short-range order patterns in Mg66Zn29Ca5 metallic glass with a unit size of ∼ 0.247 nm. Furthermore, the applied heating rate affects the glass transformation only slightly but accelerates the growth process quickly. The phase transformations occurring in annealed samples were studied by XRD, proving that crystallization starts with the formation of α-Mg + metastable Mg51Zn20. The metastable Mg51Zn20 gradually transfers to Mg7Zn3 with increasing temperature, and also Ca2Mg5Zn13 precipitates. Close to the end of crystallization, Ca2Mg6Zn3 precipitates by consuming Ca2Mg5Zn13. The Johnson–Mehl–Avrami–Kolmogorov (JMAK) model was employed to obtain the Avrami exponent of the crystallization reaction. The average slope of the Avrami plots is close to 2, indicating that crystallization progresses with diffusional growth and decreasing nucleation rate.

Effect of TiO2 content on crystallization behavior of CaO–Al2O3–SiO2–ZnO glass-ceramic glaze

In this study, TiO2 was substituted as a nucleating agent to apply CaO–Al2O3–SiO2–ZnO (CASZ)-based glass to a high-hardness crystallized glaze, and the crystallization behavior and hardness of the glaze were observed with respect to the amount of TiO2 substitution. X-ray diffraction and scanning electron microscopy analyses revealed that as the TiO2 substitution increased, a titanite crystal phase was formed in the existing anorthite crystal phase, and the crystallinity of the glaze rapidly increased. In particular, the highest crystallinity of 83.8% was observed for 12.5 wt% TiO2 substitution. The activation energy and Avrami exponent (n) of the glaze were calculated via non-isothermal analysis using differential thermal analysis, and surface crystallization behavior of n ≤ 2.5 was observed for all mixing ratios. The density of the glaze increased from 2.33 to 2.80 g cm−3 as the TiO2 substitution increased. The hardness of the glaze showed the lowest value (3.12 GPa) for the sample without TiO2 substitution and increased rapidly to 6.33 GPa or higher in the TiO2 substitution specimens.

Glass transition and crystallization kinetics of lithium modified zinc borate semiconducting glasses by non-isothermal method

Glass transition and crystallization kinetics of lithium-modified zinc borate glasses of the system 20ZnO.xLi2O.(80-x) B2O3 (x = 10, 20, 30 and 40) have been studied using the non-isothermal method of differential scanning calorimetry (DSC). The 20ZnO·10Li2O.70 B2O3 glass composition has the highest thermal stability and the glass-forming tendency among all other glasses. The activation energy associated with crystallization ((210–318) kJ/mol)), glass transition ((464–531) kJ/mol)), Avrami exponent (3) and frequency factor (2.49 × 109–2.32 × 1017) were extracted from the fitting of different theoretical models and the values are in close agreement with each other. The value of the Avrami exponent was found ∼3 thereby indicates the occurrence of volume nucleation with two-dimensional growth in the currently studied glass system. The formation of Pure monoclinic LiZnBO3 crystalline phase is observed in 20ZnO·30Li2O·50B2O3 and 20ZnO·40Li2O·40B2O3 glass compositions which is a potential candidate for electric double-layer capacitance fabrication.

Estudio cinético de la cristalización de fases grasas con agregado de fitoesteroles mediante calorimetría diferencial de barrido (DSC)

The aim of the work was to study the kinetic parameters of the isothermal crystallization of fat blends at different temperatures by differential scanning calorimetry (DSC). The fat blends are composed of fully hydrogenated rice bran oil (FHRBO) and soybean oil (SBO) at different proportions (20, 25, 30, 30, 35 and 40 % FHRBO), being both materials previously purified. In addition, some blends were selected and added a known amount of phytosterols. Kinetic parameters were quantified by applying the Avrami model that determines the induction time (generation of crystal nuclei, ti), nucleation mechanism (Avrami exponent, n) and crystal growth (kinetic constant, k). It was observed that higher percentage of FHRBO and lower crystallization temperature ti decrease and k increase. The faster kinetics observed is due to the contribution of tri-saturated triglycerides and a higher degree of supercooling. In the blend with 35 % of FHRBO, the addition of phytosterols at the concentrations studied promoted an increase in ti and a reduction in k, prolonging nucleation and generating a slow crystal growth. However, for the blend with 20% of FHRBO an increase in ti and k was observed.

Dissolution kinetics of Laves phase during homogenization heat treatment of additively manufactured Inconel 718 superalloy

The Laves phase in the as-built Inconel 718 (IN718) superalloy is known as undesirable phase, which limits the industrial applications of the manufactured parts. Post-processing in the form of the homogenization heat treatment is known as an effective method to eliminate the deleterious Laves phase, where understanding its dissolution kinetics is crucial for optimization of the heat treatment schedule. Accordingly, the IN718 nickel-based superalloy manufactured by the laser powder bed fusion (LPBF), also known as selective laser melting (SLM), was homogenized at temperatures from 950 to 1150 °C for 30 to 120 s, and the Laves phase dissolution was studied by microstructural analysis, its kinetics was modeled by Johnson-Mehl-Avrami-Kolmogorov (JMAK) analysis, and the model was validated by the second Fick's law. The activation energy for Laves phase dissolution was determined as ∼160 kJ/mol with an Avrami exponent of ∼1, which was attributed to the high dislocation density and fine microstructure of the LPBF material, and accordingly, the lattice and grain boundary diffusion of Nb in Ni were characterized as the underlying atomistic mechanisms during the dissolution of the Laves phase. These findings are based on the underlying atomistic mechanisms, which can shed light on the principles of dissolution kinetics of Laves phase in IN718 for additive manufactured parts. Moreover, the conducted comparison among LPBF, directed energy deposition (DED), and conventional casting indicated that the fabricating method and the initial segregation play key roles. In other words, due to its lower segregation degree, LPBF has faster Laves phase dissolution kinetics in comparison with other fabrication methods.

Kinetics of solid-state oxidation of iron, copper and zinc sulfide mixture

The kinetics of solid-state oxidation by air of iron, copper and zinc sulfide natural mixture, which is typical of the pyritic copper ores, is investigated. Using the high-temperature X-ray powder diffraction, thermogravimetry and differential scanning calorimetry, it was found that the process can be represented by five exothermic elementary reactions, corresponding to intensive burning of iron, copper and zinc sulfides, and two endothermic ones, associated with decomposition of copper and iron sulfates. Kinetic analysis is performed by Kissinger and Augis–Bennett methods, the model-free function mechanism was determined from y(α) master plots and iterative optimization of the kinetic parameters. The limiting steps of these reactions are nucleation and crystal growth, and the values of activation energy, pre-exponential factor and Avrami exponent are in the ranges of 140–459 kJ·mol–1, 1.41·104–3.49·1031 s–1, and 1.0–1.7, respectively. Crystallization is followed by an increase in the number of nuclei, which may be formed both at the interface and in the bulk of the ore particles, and crystal growth is one-dimensional and controlled by a chemical reaction at the phase boundary or diffusion. The results of the work can contribute to the development of theoretical ideas about the physicochemical transformations of pyritic ores and concentrates during pyrometallurgical operations.

Transformation kinetics for low temperature post-deposition crystallization of TiO 2 thin films prepared via atomic layer deposition (ALD) from tetrakis(dimethylamino)titanium(IV) (TDMAT) and water

Background: We report on the fundamental crystallization kinetics of atomic layer deposited (ALD) TiO2 thin films undergoing a post-deposition anneal (PDA) at low temperatures to probe differences in the as-deposited film microstructure. Methods: The system of study is ALD TiO2 thin films prepared from tetrakis(dimethylamino)titanium(IV) (TDMAT) and water at 120 °C, 140 °C and 160 °C followed by ex situ low temperature annealing at temperatures ranging from 140 °C to 220 °C. All as-deposited TiO2 thin films are amorphous by X-ray diffraction (XRD). Post-deposition annealing (PDA) produces large grain anatase crystals, confirmed by XRD and top-view scanning electron microscopy (SEM). A detailed SEM study is performed to quantify the nucleation and growth kinetics by fitting microstructural data to the Johnson-Mehl-Avrami-Kolmogorov (JMAK) equation. Finally, a time-temperature-transformation (TTT) diagram is constructed to summarize the differences in crystallization behavior at different ALD deposition temperatures. Results and conclusions: Fitting microstructural data to the JMAK equation reveals an Avrami exponent close to 3 with continuous nucleation, suggesting two-dimensional, plate-like crystal growth. Applying an Arrhenius relationship to the phase transformation data, the combined activation energy for nucleation and growth is found to be 1.40–1.58 eV atom-1. Nucleation rates are determined, and an Arrhenius relationship is used to calculate the critical Gibbs free energy for nucleation (~1.3–1.4 eV atom-1). As such, nucleation is the rate-limiting step for the amorphous to anatase phase transformation. ALD growth temperature is found to dictate film microstructure with lower deposition temperatures reducing the nucleation rate and leading to larger grain sizes irrespective of PDA conditions. The nucleation rate pre-exponential frequency factor increases with increasing deposition temperature, thereby increasing the likelihood for nucleation. Interestingly, it is this difference in the vibrational modes of the amorphous structure, as indicated by the variation in the nucleation rate pre-exponential frequency factor, that alters the phase transformation rates and not a change in the activation energies for the transformation.

Impact of Gd minor alloying on the crystallization kinetics of Pd40Ni40P20 bulk metallic glass

Minor alloying of metallic glasses is understood as a possible way to tune its properties and provides a study framework to the origin of their effects. Here, crystallization kinetics of Pd40Ni40P20 and minor-alloyed samples (Pd40Ni40P20)99Gd1 were studied using isothermal and isochronal calorimetry and the results were analyzed using the Johnson-Mehl-Avrami-Kolmogorov model. The addition of 1 at. % Gd into the primary alloy results in a substantial alteration of the crystallization kinetics. The Avrami exponent obtained directly from the calorimetric measurements varies from 2.5 for the ternary alloy to almost 4 for the minor-alloyed sample, indicating a change of the crystallization mechanism from a diffusion-controlled crystallization process with a constant nucleation rate and a gradually decreasing three-dimensional growth rate, to a transformation with a constant nucleation rate and a constant three-dimensional growth rate. TEM (transmission electron microscopy) microstructural analysis of the crystallized state indicates the formation of Pd-Gd-P areas, which might accelerate crystallization kinetics.

The Role of the Interface of PLA with Thermoplastic Starch in the Nonisothermal Crystallization Behavior of PLA in PLA/Thermoplastic Starch/SiO2 Composites

Corn starch was plasticized by glycerol suspension in a twin-screw extruder, in which the glycerol suspension was the pre-dispersion mixture of glycerol with nano-SiO2. Polylactide (PLA)/thermoplastic starch/SiO2 composites were obtained through melt-blending of PLA with thermoplastic starch/SiO2 in a twin-screw extruder. The nonisothermal crystallization behavior of PLA in the composites was investigated by differential scanning calorimetry. An interface of PLA with thermoplastic starch was proven to exist in the composites, and its interfacial bonding characteristics were analyzed. The interfacial binding energy stemming from PLA with thermoplastic starch exerts a significant influence on the segmental mobility of PLA at the interface. The segmental mobility of PLA is gradually improved by increasing interfacial binding energy, and consequently, the relative crystallinity on the interface exhibits progressive promotion. The Jeziorny model could well describe the primary crystallization of PLA in the composites. The extracted Avrami exponents based on the Jeziorny model indicate that the primary crystallization of PLA follows heterogeneous nucleation and three-dimensional growth. This study has revealed the intrinsic effect of the interfacial segmental mobility on the nonisothermal crystallization behavior of PLA in composites, which is of technological significance for its blow molding.

Thermal analysis and non-isothermal crystallization kinetics of Ag–Ga2Te3–SnTe telluride glasses

In this paper, the microstructure evolutions and crystallization kinetics of the newly developed Agx-[(Ga2Te3)34(SnTe)66]100−x (x = 6, 8 and 10%) telluride glasses were comprehensively investigated under non-isothermal conditions. The microscopic structure of the investigated samples were analyzed by X-ray diffraction (XRD), transmission electron microscope (TEM) and the selected area electron diffraction (SAED). The crystalline products were identified as the SnTe phase (primary crystalline phase) and Ga6SnTe10 phase. The exothermic crystallization process for any investigated samples was actually on the envelope of two overlapped peaks and could be assigned to the first crystallization event of SnTe precipitation and followed by the second crystallization event of Ga6SnTe10 phase. The crystallization mechanism and activation energies were estimated by Matusita–Sakka model under continuous heating based on the differential scanning calorimeter (DSC). For the first crystallization event, the Avrami exponent n values for each of the three investigated samples was approximately 3, suggesting the crystallization occurred through the two-dimensional growth with increasing number of nucleation. The values of n for the second crystallization event of Ga6SnTe10 phase were close to 4, indicating three-dimensional growth with a increasing number of nuclei. The activation energy Ec for both the first and second crystallization events was gradually decreased as the Ag content increased.

Atomistic study on reaction kinetics and reactivity of Ni/Al clad particles composites under shock loading.

In prior research on shock-induced reaction, the interfacial crystallization of intermetallics, which plays an important role in solid-state reaction kinetics, has not been explored in detail. This work comprehensively investigates the reaction kinetics and reactivity of Ni/Al clad particle composites under shock loading with molecular dynamics simulations. It is found that the reaction acceleration in a small particle system or the reaction propagation in a large particle system breaks down the heterogeneous nucleation and continuous growth of B2 phase at the Ni/Al interface. This makes the generation and dissolution of B2-NiAl show a staged pattern consistent with chemical evolution. Importantly, the crystallization processes are appropriately described by the well-established Johnson-Mehl-Avrami kinetics model. With the increase in Al particle size, the maximum crystallinity and growth rate of B2 phase decrease and the value of the fitted Avrami exponent decreases from 0.55 to 0.39, showing a good agreement with the solid-state reaction experiment. In addition, the calculations of reactivity reveal that the reaction initiation and propagation will be retarded, but the adiabatic reaction temperature can be elevated when Al particle size increases. An exponential decay relationship is found between the propagation velocity of the chemical front and the particle size. As expected, the shock simulations at non-ambient conditions indicate that elevating the initial temperature significantly enhances the reactivity of large particle systems and results in a power-law decrease in the ignition delay time and a linear-law increase in the propagation velocity.

Non-isothermal crystallization behavioral analysis of detonation sprayed Fe-based amorphous coating

The non-isothermal crystallization behaviors of a detonation sprayed Fe-based amorphous coating (AMC) was systematically investigated through differential scanning calorimetry, X-ray diffraction and transmission electron microscopy. The crystallization mechanism of the Fe-based AMC is analyzed and discussed in detail using a combination of the Kissinger-Akahira-Sunose and Ozawa-Flynn-Wall approaches, as well as the local Avrami exponent. The results indicate that the crystallization process of the Fe-based AMC is affected by the non-isothermal heating rate with a significantly higher initial crystallization activation energy (917.7 kJ mol−1) and first peak activation energy (479.6 kJ mol−1), indicating excellent thermal stability. After four stages of amorphous crystallization and phase transformation, the crystallization products of the equilibrium state were primarily composed of 78.5%, 11.3%, and 5.8% (Cr, Fe)23(C, B)6, α-Fe phases, and FeMo2B2 phases, respectively.

Mechanical properties and non-isothermal crystallization kinetics of novel Ti-based high-entropy bulk metallic glasses

In this work, five novel Ti- and TiZr-based high entropy bulk metallic glasses (HE-BMGs) with good glass forming ability (GFA) were developed, among which the (Ti37.31Zr22.75Be26.39Al4.55Cu9)94Ni6 alloy possesses the largest critical diameter of 9 mm. All developed HE-BMGs exhibit high yield strength and good compressive plasticity at room temperature. Especially, the (Ti37.31Zr22.75Be26.39Al4.55Cu9)94Co6 alloy with large GFA has suitable density and high specific strength (3.90 × 105 N m/kg), showing great potential in the aerospace sector. Moreover, the activation energies at characteristic temperatures of three HE-BMGs were obtained using the Kissinger method. The local Avrami exponents were calculated to analyze the crystallization mechanism of these HE-BMGs, revealing that the first crystallization process is mostly dominated by diffusion-controlled three-dimensional growth of pre-existing nuclei. In addition, all three HE-BMGs can be classified as “intermediate glasses” according to their fragility index values.

Non-isothermal crystallization kinetics study of sodium niobium phosphate glasses

Sodium niobium phosphate (SNP) glasses of composition xNb2O5–(50-x/2)Na2O–(50-x/2) P2O5 (x = 20, 30, 40 mol. %) are prepared by the conventional melt–quench technique. The non-isothermal kinetics of glass transition & crystallization of SNP glasses are studied by a differential scanning calorimeter (DSC). The dependence of glass transition temperature on the heating rate is used to deduce the activation energy of glass transition. The average activation energies of crystallization are calculated by model-free peak kinetic methods (Kissinger, Boswell, Augis-Bennet, and Ozawa). The local activation energies for crystallization with the volume fraction crystallized is estimated by linear iso-conversional methods (Kissinger-Akahira-Sunose, Starink, Tang, Flynn-Wall-Ozawa, and Various heating rates (VHR)) and by Friedman differential method. Avrami exponents are deduced to understand the nucleation and growth of various crystalline phases formed on heat treatment of SNP glasses. The change in the local Avrami exponent with the crystallized volume fraction confirms that the crystallization process occurs through volume nucleation, mainly with 3D growth. SEM analysis explored the crystalline morphologies and revealed the evolution of sheaf-like crystals.

Structure investigation of AlFeNiTiZn nanocrystalline high entropy alloy

The AlFeNiTiZn high entropy alloy with a mean crystallite size of 35–45 nm was synthesized within a two-stage process. Firstly, as a powder form using a planetary ball mill in an argon atmosphere and after that compressed the powder samples and sintered them in tube furnace as bulk samples. The X-ray diffraction, scanning electron microscopy and transmission electron microscopy techniques were used to examine the structural and morphological changes during the process. The two-phase solid solution (FCC + BCC) was formed after mechanical alloying. In addition to FCC + BCC, gahnite (ZnAl2O4) was synthesized after sintering. A differential scanning calorimetry analysis has also confirmed that recrystallization took place at 311 °C. Nucleation and growth were adequate explanations for the mechanochemical synthesis of the AlFeNiTiZn high entropy alloy based on Johnson-Mehl-Avrami model. An interface-controlled growth was the conversion mechanism based upon the Avrami exponent. According to a vibrating sample magnetometer, both as-milled and as-sintered alloys have semi-hard magnetic properties with 37.42 and 25.43 emu/g saturation magnetization, respectively. In sintered HEA, the microhardness was measured to be about 724 ± 15 HV.

Metal Organic Framework Cubosomes

AbstractWe demonstrate a general strategy for the synthesis of ordered bicontinuous‐structured metal organic frameworks (MOFs) by using polymer cubosomes (PCs) with a double primitive structure (Im m symmetry) as the template. The filling of MOF precursors in the open channel of PCs, followed by their coordination and removal of the template, generates MOF cubosomes with a single primitive topology (Pm m) and average mesopore diameters of 60–65 nm. Mechanism study reveals that the formation of ZIF‐8 cubosomes undergoes a new MOF growth process, which involves the formation of individual MOF seeds in the template, their growth and eventual fusion into the cubosomes. Their growth kinetics follows the Avrami equation with an Avrami exponent of n=3 and a growth rate of k=1.33×10−4, indicating their fast 3D heterogeneous growth mode. Serving as a bioreactor, the ZIF‐8 cubosomes show high loading of trypsin enzyme, leading to a high catalytic activity in the proteolysis of bovine serum albumin.

Metal Organic Framework Cubosomes.

We demonstrate a general strategy for the synthesis of ordered bicontinuous-structured metal organic frameworks (MOFs) by using polymer cubosomes (PCs) with a double primitive structure (Im m symmetry) as the template. The filling of MOF precursors in the open channel of PCs, followed by their coordination and removal of the template, generates MOF cubosomes with a single primitive topology (Pm m) and average mesopore diameters of 60-65 nm. Mechanism study reveals that the formation of ZIF-8 cubosomes undergoes a new MOF growth process, which involves the formation of individual MOF seeds in the template, their growth and eventual fusion into the cubosomes. Their growth kinetics follows the Avrami equation with an Avrami exponent of n=3 and a growth rate of k=1.33×10-4 , indicating their fast 3D heterogeneous growth mode. Serving as a bioreactor, the ZIF-8 cubosomes show high loading of trypsin enzyme, leading to a high catalytic activity in the proteolysis of bovine serum albumin.

Crystallization Kinetics of Modified Nanocellulose/Monomer Casting Nylon Composites.

Polyisocyanate and caprolactone were used to chemically functionalize nanocellulose (CNF). Composites of CNF, caprolactone-modified nanocellulose (CNF-CL) and polyisocyanate-modified nanocellulose (CNF-JQ)/MC nylon were fabricated by anionic ring-opening polymerization. The effects of the crystal structure, crystal morphology and crystallization process of MC nylon composites have been characterized by wide-angle X-ray diffraction (WAXD), polarized optical microscopy(POM) and differential scanning calorimetry (DSC). Isothermal crystallization kinetics were analyzed using the Avrami equation, and the crystallization rate, half-time, and Avrami exponent were calculated. The results show that the nucleation effects of CNF-JQ/MC nylon composites is increased with the CNF-JQ increase, and it is best compared with MC nylon, CNF/MC nylon and CNF-CL/MC nylon composites, so CNF-JQ can play the role of effective nucleating agent in MC nylon. We also discussed the non-isothermal crystallization of the composites. Analysis of the Jeziorny and Mo model demonstrates that the Zc values of CNF, CNF-CL, CNF-JQ/MC nylon composites increase, and the F(T) values decrease in order. This indicates that CNF-JQ can better promote the crystallization rate of non-isothermal crystallization of MC nylon. The results of this work demonstrate that CNF-JQ can be an effective nucleation agent and increase the crystallization rate of MC nylon compared with CNF-CL. The activation energy of the composites was studied using the kissing method, and the results showed that CNF-CL decreased the activation energy of MC nylon, and CNF and CNF-JQ increased the activation energy of MC nylon.

Microstructure evolution and mechanical properties of the Al-Cu-Mg-Ag alloy during non-isothermal aging

In this work, the effect of non-isothermal aging treatment with the heating rate of 20, 40 and 60 °C/h on the precipitation behavior and mechanical properties of the Al-Cu-Mg-Ag alloy were investigated by differential scanning calorimetry (DSC) analysis, transmission electron microscopy (TEM) and high-angle annular dark field – scanning transmission electron microscopy (HAADF-STEM) observation, as well as hardness and tensile tests. The activation energy and Avrami exponent associated with the precipitation of Ω phase were calculated based on the non-isothermal DSC experiments with various heating rates. The size distribution and number density of Ω plates in the α-Al matrix under peak-aged condition were quantitatively counted. Besides, A non-isothermal aging kinetics model proposed was applied to evaluate the heating aging treatment (HAT) process of the Al-Cu-Mg-Ag alloy. Results indicate that HAT modifies the size and density of Ω phase, thereby enhancing the mechanical properties of the Al-Cu-Mg-Ag alloy. HAT promotes the precipitation of Ω phase and shortens the aging time for the alloy to reach the peak-aged condition. It is interesting that the size distribution of Ω plates shifts to larger values with the increase of the heating rate during the HAT process.

Nonisothermal melt crystallization kinetics of laser-irradiated Pd/PVA nanocomposite

In the present work, we used the ex situ casting technique to synthesize a nanocomposite (NC) of polyvinyl alcohol (PVA) and nanosize palladium (Pd). The Pd has a particle size in the range from 2 to 22 nm with 10 nm on average. Samples from the synthesized NC have been irradiated with different fluences ranging from 2 to 20 J/cm2 from GaAs infrared pulsed laser (5-watt power, 904 nm wavelength, 200 ns pulse duration, 1200 Hz frequency and 0.28 cm2 spot area). Nonisothermal crystallization kinetics of the synthesized NC was investigated using differential scanning calorimetry (DSC) with different cooling rates. The Jeziorny and Mo approaches were applied to describe the nonisothermal analysis. Several nonisothermal kinetic parameters, such as the crystallization peak temperature (Tc ), the enthalpy of crystallization (ΔHc ), the degree of crystallinity (Xc ), the crystallization halftime (t 1/2), the Avrami exponent (n) and the activation of crystallization (Ea ) were evaluated and interpreted as a function of laser fluences. The results indicated that the incorporation Pd nanoparticles into the PVA matrix accelerate the crystallization process, while the laser radiation causes chain crosslinking that reduces the crystallinity.