Explosive Particles Research Articles

Thermal properties regulation of primary explosive based on adhesives’ composition effect

Abstract With the upgrading and development of weapons, primary explosive charge methods based on extrusion/printing technology had become important direction for the support capacity improvement for in service and novel equipment. Binders as the key component in extrusion/printing based primary explosive charge technology, its influence on primary explosives hadn’t been investigated, which shown important influence on energetic materials’ safety and reliability. Thus, primary explosive-binder compositions, (Nitrocellulose (NC), ethylcellulose(EC), and Viton (F) were employed as typical binders; meanwhile, lead azide (LA), silver azide (SA), and lead styphnate (LTNR) were employed as typical primary explosives), were prepared via water phase suspension method, and fully characterized its structure and thermal decomposition property. Hollow sphere structure was formed with NC and EC as binders, nanosheet could be find in the primary explosive-EC compositions. F based compositions shown primary explosive nano particles and aggregate blocks. EC shown more obvious influence effect to azide based primary explosives, which increased the decomposition temperature of LA, decreased the decomposition temperature of SA. F shown enhancement effect to LA’s thermal stability, and weak influence on the thermal stability of SA. These results could be attributed to the nanosheets structure of NC and EC in the composites. For LTNR, EC and F shown the weak effect to its decomposition temperature.

Preparation of spherical HMX@PDA-based PBX by co-axial droplet microfluidic technology: Enhancing the interfacial effect and safety performance of composite microspheres

Surface engineering plays a crucial role in improving the performance of high energy materials, and polydopamine (PDA) is widely used in the field of energetic materials for surface modification and functionalization. In order to obtain high-quality HMX@PDA-based PBX explosives with high sphericity and a narrow particle size distribution, composite microspheres were prepared using co-axial droplet microfluidic technology. The formation mechanism, thermal behavior, mechanical sensitivity, electrostatic spark sensitivity, compressive strength, and combustion performance of the microspheres were investigated. The results show that PDA can effectively enhance the interfacial interaction between the explosive particles and the binder under the synergistic effect of chemical bonds and the physical "mechanical interlocking" structure. Interface reinforcement causes the thermal decomposition temperature of the sample microspheres to move to a higher temperature, with the sensitivity to impact, friction, and electrostatic sparks (for S-1) increasing by 12.5%, 31.3%, and 81.5% respectively, and the compressive strength also increased by 30.7%, effectively enhancing the safety performance of the microspheres. Therefore, this study provides an effective and universal strategy for preparing high-quality functional explosives, and also provides some reference for the safe use of energetic materials in practical applications.

Parameter characterization of the PBM-DEM method in numerical simulation of shallow buried mine explosions

Abstract To investigate the impact of various parameters on the numerical simulation of shallow buried mine explosions through the particle explosion method and discrete element method, this paper adopts a coupled method of particle blast method and discrete element method, namely the PBM-DEM method, to simulate the response of AL-6XN stainless steel plate under shallow buried mine explosions. This article first combines the experimental results of Børvik to validate the precision of the PBM-DEM approach. Then, the influence of particle quantity, interaction parameters between sand particles, and interaction parameters between sand particles and plate on the outcomes of the numerical simulations are analyzed. The analysis reveals that as the quantity of explosive particles rises, the central displacement and maximum kinetic energy of the plate escalate. In contrast, these values decrease as the number of sand particles increases. The interaction parameters between sand particles have almost no effect on the numerical simulation results. The damping and stiffness parameters between the sand particles and the plate have a pronounced effect on the numerical simulation results, and the center displacement and peak kinetic energy of the plate rise as the damping and stiffness parameters between the sand particles and the plate increase.

Preparation and Molecular Dynamic Simulation of Superfine CL-20/TNT Cocrystal Based on the Opposite Spray Method.

In view of the current problems of slow crystallization rate, varying grain sizes, complex process conditions, and low safety in the preparation of CL-20/TNT cocrystal explosives in the laboratory, an opposite spray crystallization method is provided to quickly prepare ultrafine explosive cocrystal particles. CL-20/TNT cocrystal explosive was prepared using this method, and the obtained cocrystal samples were characterized by electron microscopy morphology, differential thermal analysis, infrared spectroscopy, and X-ray diffraction analysis. The effects of spray temperature, feed ratio, and preparation method on the formation of explosive cocrystal were studied, and the process conditions of the pneumatic atomization spray crystallization method were optimized. The crystal plane binding energy and molecular interaction forces between CL-20 and TNT were obtained through molecular dynamic simulation, and the optimal binding crystal plane and cocrystal mechanism were analyzed. The theoretical calculation temperature of the binding energy was preliminarily explored in relation to the preparation process temperature of cocrystal explosives. The mechanical sensitivity of ultrafine CL-20/TNT cocrystal samples was tested. The results showed that choosing acetone as the cosolvent, a spraying temperature of 30 °C, and a feeding ratio of 1:1 was beneficial for the formation and growth of cocrystal. The prepared CL-20/TNT cocrystal has a particle size of approximately 10 μm. The grain size is small, and the crystallization rate is fast. The impact and friction sensitivity of ultrafine CL-20/TNT cocrystal samples were significantly reduced. The experimental process conditions are simple and easy to control, and the safety of the preparation process is high, providing certain technical support for the preparation of high-quality cocrystal explosives.

Aerodynamic resuspension of irregular flat micro-particles

This study investigates the role of particle shape on the aerodynamic resuspension process of irregular flat micro-particles on a substrate. We propose that these particles resuspend at higher velocities than spherical ones of the same size under the same aerodynamic forces. Two sets of data are analyzed to test the argument, the first from experiments we conducted using crushed glass particles (ranging from 80 μm to 300 μm) and the second from published data on RDX explosive residue particles (sized between 10 μm and 25 μm) published previously.We particularly analyze the shape factors of the particles used in the experiments and introduce them into a Monte Carlo (MC) simulation model. The probabilities for the time evolution of the resuspension process are calculated through a Markov chain of states. The transition probabilities entail the balance between the forces and moments involved in the mechanisms for particle detachment from the surface.The particle resuspension rate as a function of the fluid velocity is evaluated both experimental and numerically. Additionally, we assess the removal efficiency for different particle size ranges whenever possible.Both experimental and numerical results demonstrate that the resuspension fraction of irregular flat particles is significantly lower than for equally sized glass microspheres under the same conditions. Simulations corroborate previous experimental findings, indicating that smaller irregular particles exhibit higher removal efficiency. According to the MC model results, irregular particles detach by sliding rather than rolling.

Preparation and safety study of TKX-50/CL-20 composite explosives

ABSTRACT CL-20, as the best comprehensive high nitrogen energetic material, plays an important role in weaponry, equipment, and national defense. TKX-50, as a new type of ionic explosive, is commonly used for composite explosives due to its excellent desensitization effect. This work combines TKX-50 and CL-20, and then encapsulates them using demulsification method. TKX-50/CL-20 composite explosives were successfully prepared at the binder dosage of only 1.5 wt.%, which showed good encapsulation effects. The results showed that the Polyvinyl butyraldehyde (PVB) and wax were successfully coated on the surface of the explosive particles, and the crystal structure of CL-20 in the composite did not change, while the excellent detonation property of ε-CL-20 is retained. Our study found that TKX-50 has a catalytic effect on the decomposition of CL-20, and when mixed alone, the activation energy of CL-20 is significantly reduced. Furthermore, the activation energy of the TKX-50/CL-20 composite explosive prepared has hardly changed compared to CL-20, and it has better thermal stability compared to TKX-50/CL-20 (1:1). The impact sensitivity and friction sensitivity of TKX-50/CL-20 composite explosives have also been significantly improved, with 2 J and 96 N higher than the TKX-50/CL-20 (1:1) raw materials, respectively, demonstrating good desensitization effect.

Influence mechanism of the diameter of the energy accumulation hole on the bi-directional cumulative tension blasting

This study focuses on evaluating the influence of the energy accumulation hole diameter on bi-directional cumulative tension blasting. Firstly, the penetration depth of bi-directional cumulative tension blasting is determined, followed by an analysis of the corresponding fracture mechanics behavior. Secondly, the Smooth Particle Hydrodynamics (SPH) method is used for numerical analysis of the bi-directional cumulative tension blasting process, and the Johnson-Holmquist constitutive model is then employed to examine the dynamic process during tensile blasting-induced cracking. This analysis provides insights into damage development, particle distribution, stress distribution, and crack propagation in the rock at different opening diameters. The findings reveal that, except for the 2 mm case, bi-directional cumulative tension blasting effectively produces directional cracks aligned with the energy accumulation direction. For hole diameters between 4–8 mm, linear through cracks form in the energy accumulation direction. However, a 2 mm diameter opening only generates short shear cracks around the blast hole. With energy accumulation hole diameters ranging from 10–14 mm, the crack propagation depth is insufficient for complete penetration, despite the presence of linear cracks in the energy accumulation direction. When diameter exceeds 14 mm, symmetrical airfoil cracks appear in non-concentrated energy directions, with larger diameters resulting in shorter crack propagation lengths. During the directional cracking process for hole diameters of 4–8 mm, explosive particles facilitate crack expansion in width and length through the action of a “gas wedge.” On-site blasting tests confirm the excellent directional pre-splitting effect of bi-directional cumulative tension blasting.

Fluorescent probe/hydrogel-based portable platform for ultrasensitive on-site detection of explosive particles containing nitrite

On-the-spot identification of solid or deposited explosive airborne particulates through luminescence techniques plays a vital role in homeland security, environmental analysis, and medicolegal diagnosis. However, integrating the rapid collection of solid explosive particles with fluorescent probe equipment and developing a direct and ultrasensitive detection technique for explosive particles on-site remain a formidable challenge in the fluorescence sensing field. In this study, we developed a portable detection platform based on a complex system using a combination of fluorescence probes/hydrogels and smartphone technology, which could not only quickly collect and capture explosive airborne particles but could also immediately synchronously realize ultrasensitive detection. The newly designed fluorescent probe 2-(5-chloro-1H-benzo [d] imidazol-2-yl) aniline (10-CBMA) exhibited superior recognition ability compared to two other probes, namely, BMA and 9,10-CBMA, for nitrite solution and solid conditions, with a low detection limit (8.558 × 10−8 M, solution), a quick detection time (2 mins, solid), and excellent specificity even in the presence of other interfering ions. In addition, by utilizing the robust photography capabilities of smartphones, nitrite particles could be quickly recognized on the spot. Overall, this portable platform based on fluorescence probes/hydrogels for ultrasensitive nitrite solid detection strategy provided in-depth insights into advancing explosive detection.

Nano-Voids in Ultrafine Explosive Particles: Characterization and Effects on Thermal Stability.

Ultrafine explosives show high safety and reliable initiation and have been widely used in aerospace, military, and industrial systems. The outstanding performance of ultrafine explosives is largely given by the unique void defects according to the simulation results. However, the structures and effects of internal nano-voids in ultrafine explosive particles have been rarely investigated experimentally. In this work, contrast-variation small angle X-ray scattering was verified to reliably measure the structures of internal nano-voids in ultrafine explosive 2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105) and 2,2',4,4',6,6'-hexanitro diphenylethylene (HNS). The size of nano-voids is around 10 nm, and the estimated number of nano-voids in a single particle is considerable. Moreover, the thermal stability of ultrafine LLM-105 was improved via changing the structures of nano-voids. This work provides a methodology for the study of nano-void defects in ultrafine organic particles and may pave the path to enhance the performance of ultrafine explosives via defect engineering.

Dependence of polyethylene combustion dynamics in a 1 m<sup>3</sup> chamber on particle size

Introduction. The results of a standard study on the explosion hazard of polyethylene air suspensions (PES) can contribute to the theory of turbulent combustion. For example, analysis of polydispersity data and values of the PES lean combustion limit in a 1 m3 chamber helped to identify the maximum size of explosive particles d*m,t ≈ 100 µm (Poletaev, 2014). In this work, a relationship was obtained between the dynamics of PES combustion in a 1 m3 chamber and the average particle size of the suspension, which is understood as the average particle size of its explosive fraction d*50.Initial data. Well-known findings of a study on the explosion of 28 polyethylene specimens in a 1 m3 chamber were used. Continuous functions of specimen particles distribution by size, necessary for calculating d*50, were represented using the Rosin-Rammler distribution.Combustion dynamics. The dynamics of PES turbulent combustion in a 1 m3 chamber is described by the maximum rate of air suspension burnout Ub. Ub was calculated according to the formula (Kumar, 1992) intended for gas-air mixtures by substituting PES explosion parameters into this formula.Results and its discussion. The graph, describing the dependence of the complex d*50Ub on d*50, is provided. The averaged value of the complex (≈ 45 µm · (m/s)) is constant in the range 40 µm < d*50 < 90 µm. The latter is typical for the product of the particle size and the normal velocity of laminar flame in liquid aerosols (Myers, 1986), which indicates similarity between the effect of particle dispersion and dynamics of turbulent and laminar combustion of the aforementioned heterogeneous mixtures.Conclusions. The dispersive capacity of an explosive polydisperse polyethylene specimen is determined by the average particle size of the explosive fraction of the specimen d*50. The similarity of combustion patterns indicates the proximity of propagation mechanisms typical for turbulent flame, typical for PES, and laminar flame, typical for liquid aerosols.

High signal-to-noise-ratio ultrasonic imaging of crack defects in particles filled composite explosives

<sec>Polymer bonded explosive (PBX) is a kind of composite material with highly filled molding explosive particles (normally more than 95%) and a small quantity of binders (less than 5%). The effective detection of internal cracks in PBX is of great significance in evaluating structural integrity and safety reliability.</sec><sec>Ultrasonic phased array detection and imaging methods show great advantages and potential in detecting crack defects. But acoustic test results indicate that the PBX has unique characteristics with low longitudinal wave velocity (～3000 m·s<sup>–1</sup>) and strong attenuation (attenuation coefficient ～400 dB·m<sup>–1</sup> for 2.5 MHz ultrasound). When the defect is imaged by traditional ultrasonic total focusing method (TFM), the structural noises at the boundaries between particles lead to low signal-to-noise ratio (SNR) in the FMC signals and strong background noise in reconstructed image, which will disturb the detection of cracks.</sec><sec>To realize the high SNR imaging of crack defects in PBX, an ultrasonic imaging algorithm based on baseband nonlinear synthetic focusing (BB-NSF) is proposed. By utilizing the spatial coherence of the received signals in full matrix capture (FMC) data, the pixel intensity at defect position can be enhanced while the background noise can be drastically weakened. The delay rule of the algorithm is modified according to the characteristics of PBX surface configuration. In this way, the high SNR imaging of crack defects with different orientations of PBX surface configuration is realized, and the quality of the reconstructed images is compared and evaluated quantitatively. Meanwhile, the base band transformation in calculation process optimization could significantly reduce calculation burden and increase imaging efficiency.</sec><sec>Experimental results show that the proposed algorithm can effectively suppress background noise and significantly improve the ability to detect the PBX cracks. The effective suppression to background noise makes the defect more highlighting and distinguished easily. For the BB-NSF algorithm, spatial coherence coefficient <i>p</i> is a crucial parameter used for dynamically regulating the SNR of reconstructed image. When <i>p</i> value is more than 2.0, the SNR of the ultrasonic reconstructed image of PBX crack defect is improved by more than 10 dB compared with that of the traditional linear synthetic focusing imaging. With the increase of <i>p</i> value, the SNR is further improved, while the calculation efficiency for a single image is almost kept stable. Moreover, the increase of SNR to some extent will improve the far-field detect capability.</sec><sec>Besides, with the BB-NSF algorithm, flexible transducer inhibits different imaging characteristics of for cracks with different orientations and depths in curved PBX specimens. For defects with large orientation angle and buried depth, the tip, root and shape of cracks can be completely present. For defects with small orientation angle and buried depth, part of shape and contour features will be lost.</sec><sec>In conclusion, the BB-NSF algorithm shows the advantage of high SNR and calculation efficiency in imaging PBX cracks, and exhibits great application prospect in imaging internal defects of other strongly attenuated composites.</sec>

Sphericity and roundness for three-dimensional high explosive particles by computational geometry

Sphericity and roundness for three-dimensional high explosive particles by computational geometry

Three-dimensional discrete element method to simulate the ignition and combustion of HMX explosives under hot spots

The key to the initiation of condensed explosives is the hot spot which is universally acknowledged. Different hot spots will be produced in explosive particles under different impacts, making quite a discrepancy in the combustion and deflagration processes. In this paper, the ignition and combustion behaviors of the cyclotetramethylene-tetranitramine (HMX) explosive particles under hot spots, and the effect of particle size on the ignition and combustion behavior are developed based on the three-dimensional discrete element method (3D-DEM). The simulation results emphasize that the number of hot spots in the explosive will have an important impact on the ignition and combustion of the explosive. The deflagration performance of the explosive may be inhibited when the number of hot spots generated is too large. In addition, the difference in particle size of explosives can also cause differences in ignition sensitivity and deflagration performance. It is believed that fine explosives are easier to ignite, which is consistent with the experimental observation. The simulation results also reveal a positive correlation between ignition sensitivity and deflagration performance. • The HMX with more hot spots may tend to burn rather than explode. • The HMX with small particle size is more sensitive and has better deflagration. • The apparent pressure of HMX under hot spots is negative at the beginning.

A laboratory rill study of IMX-104 transport in overland flow

The deposition of explosive contaminants in particulate form onto the soil surface during low-order detonations can lead to ground and surface water contamination. The vertical fate and transport of insensitive munitions formulation IMX-104 through soil has been thoroughly studied, however the lateral transport of explosive particles on the surface is less known. The objective of this research was to understand the impact of overland flow on the transport of IMX-104 constituent compounds 3-nitro-1,2,4-triazol-5-one (NTO), 2,4-dinitroanisole (DNAN), hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX). The effect of overland flow was examined in a rill flume using several flow rates (165-, 265-, and 300-mL min−1) and IMX-104 particle sizes (4.75–9.51 mm, 2.83–4.75 mm, 2–2.83 mm, and <2 mm). We found that the smaller particles were transported more in solution and with the sediment compared to the larger particles, which had a higher percent mass remaining on the surface. As flow rate increased, there was an increase in the percent mass found in solution and sediment and a decrease in the percent mass remaining on the surface. NTO fate was dominated by transport in solution, while DNAN, RDX and HMX were predominantly transported with the sediment. This research provides evidence of the role of overland flow in the fate of energetic compounds.

An improved mesostructure construction method for precise modeling of polymer-bonded explosives

The polymer-bonded explosives (PBXs) contain randomly distributed particles with irregular shapes, high volume fraction (greater than 90%) and gradation feature of size. The precise mesostructure modeling is essential to predict the mechanical properties of PBXs. This study proposes a Voronoi-based mesostructure modeling method of PBXs by considering the real characteristics of PBXs, which can meet both the requirements of high volume fraction and specified size gradation of explosive particles. The key point of the method is to place the particles generated by Monte Carlo method into the representative volume element of PBXs by proposing an improved random walking algorithm (RWA). In the improved RWA, a subregion-independent particle delivery criterion is introduced to enhance the placement efficiency, and an overlapping judgment criterion by tolerating slight overlaps between particles is applied to make the size of placed particles match the grading relationship better. Numerical examples have been provided to verify the correctness and efficiency of the proposed mesostructure modeling method.

Estimating the maximum size of explosive iron sulfide particles

Introduction. There are estimates of the maximum size dcr of explosive particles of the two types of sulfide ores. The estimates are based on a qualitative approach to the dispersion analysis of combustible ore specimens (Soundararajan, Amyotte &amp; Pegg, 1996): 49 μm &lt; dcr, PO &lt; 63 μm for pyrrhotite (PO) and 85 μm &lt; dcr, PY &lt; 145 μm for pyrite (PY). The task was to refine these estimates using the quantitative method of the mentioned analysis, taking into account the lower explosive limit (LEL) of flame propagation in terms of ore suspensions. Experimental data processing method. Continuous functions F of particle size distribution d were constructed for the two polydisperse specimens of pyrrhotite (LELPO,1 = 475 g/m3 and LELPO,2 = 1,375 g/m3) and two polydisperse specimens of pyrite (LELPY,1 = 375 g/m3 and LELPY,2 = 500 g/m3). The obtained functions FPO,1(d), FPO,2(d), FPY,1(d) and FPY,2(d) were converted using Rosin – Rammler distributions, filling the gaps between the discrete data of the grain-size analysis of the specimens. dcr rating. The procedure for estimating dcr (Poletaev, 2014) was employed to find the values of dcr, PO and dcr, PY using the following equations: FPO,1(dcr, PO)/FPO,2(dcr, PO) = LELPO,2/LELPO,1 and FPY,1(dcr, PY)/FPY,2(dcr, PY) = LELPY,2/LELPY,1. The solutions were presented in the visual graphic format.Discussion of the results. Due to the low values of explosion parameters of pyrrhotite and pyrite in a 20‑liter chamber (maximum explosion pressure Pmax ≤ 350 kPa, index Kst ≤ 2 MPa ∙ m/s), the validity of classifying ores as explosive dusts was discussed. Low explosion values have proven that sulfur is the main fuel in the air suspension. The explosiveness of ores is proven empirically (Selle &amp; Zehr, 1954) by estimating the combustion temperature, which exceeds 1,000 °С.Conclusions. The values of dcr for sulfide ores have been refined: for pyrrhotite, dcr = 40 μm; for pyrite dcr = 107 μm. In the air suspensions of ores, only sulfur is burnt out, which substantially reduces the explosiveness of ores.

Improving particle collection efficiency of sampling wipes used for trace chemical detection.

Improvement of the particle collection efficiency of sampling wipes is desirable for optimizing the performance of many wipe-based chemical analysis techniques used for trace chemical screening applications. In this note, commercially available Teflon coated fiberglass and calendered Nomex sampling wipes were modified by mechanically scoring the wipe surface to produce topography that promoted enhanced and localized particle collection. Wipe surface modifications improved particle collection efficiency, relative to unmodified wipes, by factors of 3 to 13 depending on sampling conditions, wipe type, and surface sampled. Improvements were demonstrated for both model polystyrene latex microspheres and inkjet printed explosive particles. The modifications also concentrated particles into pre-defined locations on the wipe which can be engineered to ensure maximum overlap with the thermal desorber of a trace contraband detection system allowing for more effective analysis of collected trace residues.

Discrete element method simulation of energy dissipation mechanisms of HMX explosive particles under drop-weight impact

A thermal-mechanical coupling model describing energy dissipation of cyclotetramethylene-tetranitramine (HMX) explosive particles subjected to drop-weight impact is developed based on the discrete element method (DEM). The energy dissipation resulting from plastic deformation, sliding friction and rolling friction due to the interaction of HMX explosive particles can be effectively captured during the impact loading process by DEM. The simulation results illustrate that the energy dissipation increases with the increase of drop-weight height, particle size, and moment of inertia of particle, but the energy dissipation decreases when the sample mass increases from 40 mg to 55 mg at the same impact loading condition. Moreover, it is found that the energy dissipation is dominated by interparticle friction dissipation in the absence of internal defects such as cracks or pores, which is in agreement with previously published results. Furthermore, this work reveals that the main contribution of friction dissipation is derived from rolling friction dissipation.

Construction of CL‐20 Surface Layer with Different Wetting Properties and its Effect on Slurry Rheological Behavior and Mechanical Sensitivities

AbstractTo have a deep understanding of the effects of surface wettability on the mechanical sensitivity and rheological characteristics of PBX slurry, CL‐20 particles with hydrophilic property was prepared through a polymerization process of dopamine, and CL‐20 particles with hydrophobic property were prepared through a condensation polymerization process of hexadecyltrimethoxylsilane. The morphology, surface element content and surface wettability of CL‐20 crystals before and after modification were characterized by scanning electronic microscope (SEM), X‐ray photoelectron spectroscopy (XPS), and contact angle test. The rheological characteristics of CL‐20 based PBX slurry showed that the interaction between explosive particles and binder was changed with different surface wettability of CL‐20. The weaker interaction between CL‐20@hydrophobic and binder lead to weaker solid‐liquid friction, resulted in lower apparent viscosities of CL‐20@hydrophobic based PBX slurry at high shear rate. The mechanical sensitivity of wax coated CL‐20 with different surface wettability was tested. CL‐20@hydrophobic‐wax exhibited better mechanical stability compared to CL‐20‐wax and CL‐20@hydrophilic‐wax, probably owning to the weaker interaction between CL‐20@hydrophobic surface and wax.

Evolution of nanosecond laser-induced phase explosion based on a high-speed continuous imaging system

A high-speed continuous imaging system is established based on the principle of multiwavelength shadow imaging with a 15-ns exposure time and 1-ns frame interval. Furthermore, the spatiotemporal evolution of phase explosion products induced by Nd: YAG nanosecond laser ablation of aluminum was observed. The results show that, at the laser flux of 1.34 J/cm2, only shockwave is caused by strong evaporation; above the laser flux of 2.05 J/cm2, the shadow image shows significant explosive particles jet. When the injected laser flux reaches 3.32 J/cm2, the plasma explosion is accompanied by the phase explosion. Moreover, at a laser flux between 1.34 and 2.05 J/cm2 the velocity of shockwave fronts surges owing to the phase explosion. At a laser flux of 2.86–3.32 J/cm2, the wavefront velocity resurges under the effects of phase explosion and plasma explosion.