Clusters Of Grains Research Articles

Multi-scale surface folding in metal cutting

In this work, commercially pure small-grained copper is used to investigate the nature of plastic flow through in situ image analysis supported by extensive electron backscatter diffraction characterization of the chip. Non-laminar sinuous flow, manifested with surface perturbations (bumps) and folds, produces a highly heterogeneous strain field during cutting. A series of mushroom-shaped morphology, termed as large bumps, separated by large folds on the free surface of the chip are captured in high-resolution field emission scanning electron microscopy. Large bumps or folds, captured in the high-speed camera, consist of many medium and small-size bumps. While the size of the small bump is comparable with the grain size of the base metal, a cluster of grains takes part in forming medium-size bumps. The pinning points for the small size bumps are either grain boundary or hard grains. The hard grains also act as pinning points for the medium size bump. The bump boundaries (folds) are characterized by higher strain and greater refinement of grains, whereas, less strain and larger elongated grains are the characteristics of the central region of the bumps. The evolution of different length scale features on the free surface is discussed in terms of the orientation of grain, position of the grains on the surface, and induced strain in the chip. This study suggested that the development of folding at different length scales is capable of providing deeper insight into the formation of a wide variety of chip morphology observed during the cutting of metals.

Functionalization of morphology in optimization of dielectric, electrical/impedance modulus, and relaxation mechanisms of Co-Ni doped M-type Sr nanoferrites

In this article, novel M-type hexaferrites SrCoxNixFe12−2xO19 were synthesized using the sol–gel method. The phase structure was characterized by x-ray diffraction, grain morphology was investigated from scanned electron micrographs, and dielectric/electric/impedance characteristics were analyzed in the frequency range of 100 Hz to 2 MHz. X-ray diffraction (XRD) revealed the formation of hexaferrites without any secondary phase. The grain size and distribution were significantly affected by Co-Ni dopants and there was an observation of cluster of grains, grain agglomerates, and improved inter-grain connectivity. The substitution of Co-Ni caused a reduction in crystallite size from 41.47 to 23.14 nm and the dielectric constant/loss tangent varied non-monotonically. The electric modulus indicated a non-Debye type relaxation and the charge transport mechanism exhibited conductivity relaxation to be more dominant than dielectric relaxation. The prepared ferrites show a large dielectric constant and hence are suitable for use in transformer core and storage media. The correlation of simulated grain/grain boundary parameters with morphology, dielectric parameter, and electric modulus has been presented.

Phase composition, structure and properties of B<sub>4</sub>C–TiB<sub>2</sub> ceramics produced by hot pressing

Composite ceramic materials based on B4C with the addition of TiB2 in amounts of 0, 10, 20, 25 and 30 mol. % have been studied. Titanium diboride was synthesized from TiO2 powder and nanofibrous carbon using the boron carbide method in an induction furnace at 1650 °C in an argon atmosphere. The samples were produced by hot pressing at 2100 °C and 25 MPa in an argon environment. The phase composition was determined, and the apparent density and open porosity of the experimental materials were measured. The microstructure was assessed using optical and scanning electron microscopy. The investigations revealed that an increase in the TiB2 content reduces the open porosity while concurrently enhancing the relative density of the boron carbide ceramics. For a sample containing 30 mol. % TiB2 , the open porosity and relative theoretical density were 1.6 and 99 %, respectively. Using XRD and XRS analyses established that the synthesized materials are comprised of two phases: B4C and TiB2 . The average grain size of TiB2 was 0.85 ± 0.02 µm for the sample with 10 mol. % TiB2 and 8.90 ± 0.25 µm for the material with 30 mol. % TiB2 . It was found that at higher TiB2 concentrations, large clusters of grains are formed. The destruction pattern of B4C grains is intragranular, while TiB2 grains are characterized by intergranular destruction. For a sample containing 30 mol. % TiB2 , the fracture toughness was 4.97 ± 0.23 MPa∙m0.5, and the hardness was 3320 ± 120 HV0.5 . Therefore, the addition of TiB2 at these specified concentrations facilitated a 30 % enhancement in fracture toughness relative to single-phase B4C while preserving a high level of hardness.

Quantitative beta autoradiography of a heterogeneous granulite sample and implications for luminescence dating

Beta dose rate heterogeneity is a known source of scatter in OSL measurement and equivalent dose distributions. Without proper methods to describe and account for it, it can contribute significantly to the uncertainties in OSL ages. For this reason, investigating the beta dose rate (β Dr) distribution is necessary to improve the dating of heterogeneous samples. Here we present a method for quantitative and high sensitivity autoradiographic imaging of beta dose rates. It is demonstrated using highly heterogeneous granulite rock samples. The accuracy and sensitivity of this method is improved using pulsed laser stimulation, and by underground exposure of samples in an ultra-low background environment. Results are calibrated using gamma (γ)irradiation and Monte Carlo simulation and have been validated using homogeneous dose rate standards. Combining analysis of autoradiography results and SEM backscattered images of the same samples allows determination of the dose rate distributions in the different mineral phases. A significant difference between the dose rate of K-feldspar grains obtained from the imaging and the dose rates calculated using methods commonly used in OSL dating is noted because of the clustering of grains in the sample. This represents a risk of bias in age determination in coarse grained rock samples which can be analysed using dose rate imaging methods. The beta Dr spatial distributions result in a significant dose scattering received by single grains, even compared to the total dose rate. The effect of such beta dose rate distributions on OSL dating of coarse-grained crystalline materials is discussed.

Evidence of twin mediated growth in the CVD of polycrystalline silicon carbide

The origin of the 〈110〉 texture in polycrystalline 3C-SiC grown by chemical vapor deposition at different temperatures is investigated by thorough EBSD, SEM and XRD characterizations. Regarding the 〈110〉 orientation, although XRD suggests a fiber texture, closer inspection of isolated clusters of grains by EBSD reveals a high symmetrical order in-plane. The pole figures associated with these clusters are in good agreement with cross-twinned pentagonal structures in which each grain shares a common 〈110〉 axis. These structures form via twin-mediated growth involving the formation of twin plane reentrant edges that act as a preferential site for the incorporation of adatoms. A deviation from a perfect cross-twinned structure is observed and is attributed to the presence of additional parallel twins. In this study, the transition to the 〈110〉 orientation occurs when the temperature increases and the partial pressure of reactive species decreases. This can be explained by the enhancement of surface mobility that promotes surface diffusion to the twin plane reentrant edges, thus activating the twin mediated growth mechanism.

Structural, morphological, dielectric and ferroelectric properties of Nd substituted YFeO3 ceramics synthesized via sol gel auto-combustion route

The effect of Nd3+ ion substitution on the structural, morphological, ferroelectric, and dielectric properties of Y1-xNdxFeO3 (0 ≤ x ≤ 0.16) was investigated. The samples were prepared using the sol-gel auto-combustion route. The crystallite size was found to be in the range of 23 to 15 nm. The SEM exhibited that pure YFO shows an inhomogeneous shape of particles, while the substituted samples demonstrated a spherical shape and clusters of grains. The substitution of Nd3+ ions causes the splitting of vibrational characteristic bands υ1 from 450.71 to 479.1 cm−1 while characteristic band υ2 changes from 592.13.1 to 687.90 cm−1, respectively. The ferroelectric analysis indicated that polarization was 0.023 nC/cm2 to 0.007 nC/cm2 at a maximum applied field of 0.01 kV/cm. The dielectric constant of Nd3+ substituted YFO was increased as compared to pure YFO. All YFeO3 samples showed low values of tan loss (tanδ) es compared to pure YFO. Low dielectric losses of YFO suggest their utilization in multilayer chip inductors.

Parametrically upscaled crack nucleation model (PUCNM) for fatigue nucleation in titanium alloys containing micro-texture regions (MTR)

Micro-texture regions (MTRs), delineated as the clusters of grains with similar crystallographic orientations in the polycrystalline microstructure, play a significant role in fatigue crack nucleation and life of structures of Ti alloys. This paper develops a parametrically upscaled constitutive and crack nucleation modeling (PUCM/PUCNM) platform for predicting structural-scale fatigue crack nucleation in α/β Ti–6Al–4V alloys, whose polycrystalline microstructures contain MTRs. The PUCM/PUCNM platform bridges micro and macro scales through thermodynamically consistent incorporation of representative aggregated microstructural parameters (RAMPs) in macroscopic constitutive relations. A novel RAMP kMTRθc that captures both the MTR size and contrast in the overall texture is proposed to quantitatively represent the MTR intensity in the microstructure. Geometric analysis and comparison with experimental data establish the effectiveness of kMTRθc in characterizing the MTR distributions. The impact of MTR characteristics on fatigue crack nucleation is evaluated through the support vector regression (SVR)-aided Sobol analysis, based on data from crystal plasticity FE simulations of polycrystalline microstructure volumes with a grain-scale crack nucleation model. The PUCNM is uniquely suitable for the incorporation of the MTR RAMP kMTRθc in its probabilistic framework. A novel functional form is derived using the genetic programming-based symbolic regression (GPSR). The PUCM/PUCNM tool is used to simulate an engine blade under dwell loading conditions. Results exhibit the reduction of nucleation life with a higher level of MTR intensity, despite the same overall textures.

Oxide enrichment by syntectonic melt-rock interaction

Processes that enrich rocks in oxides, such as ilmenite, are controversial. Current models include magmatic accumulation, crystallisation of veins from immiscible liquids and syntectonic differentiation. In this contribution, we investigate examples of oxide enrichment in both the oceanic and continental crust. The oceanic samples are of oxide gabbros (with up to 45 vol% oxides) from the Atlantis Bank oceanic core complex, Southwest Indian Ridge. The continental sample is from the Cattle Water Pass shear zone (with up to 20 vol% oxides) associated with the intracontinental Alice Springs Orogeny, central Australia. We argue for the occurrence of an open chemical system, with melt rock reactions as a key process involved in oxide enrichment in melt-fluxed shear zones. Our detailed microstructural characterisation reveals that oxides replace silicates and form interstitial grains, grain boundary films and low dihedral angles between silicates often making up an interconnected skeletal texture. Quantitative orientation data reveals that the oxides: 1) have limited internal deformation, 2) form clusters of grains that are connected in 3D, 3) have crystal faces matching the orientation of the grain boundary of nearby newly crystallised diopside (oceanic sample) and 4) form part of the foliation defining assemblage with biotite (continental sample). This evidence suggests the oxides crystallised in the presence of melt and formed during melt-rock interaction. Syntectonic melt migration is known to result in low strain microstructures in shear zones, as the strain is accommodated by the melt that existed in the deforming rock. This produces a high strain rock with silicate and oxide minerals that show limited internal deformation. Microchemical data shows major element variability in silicates and ilmenite at the thin section scale, supporting an open chemical system with local variability in both oceanic and continental settings. It further argues that syntectonic melt migration is important in oxide enrichment. Mineral chemistry data implies that the oceanic tectonic setting involved melt-rock interaction with fractionated gabbroic melt while the continental setting involved peraluminous granite melt driving mineral replacement and enrichment of oxides. We propose that deformation assisted reactive porous flow of near liquidus melt through rocks in any tectonic setting may result in melt-rock interaction induced crystallisation of oxides in preference to silicates and that with high time-integrated melt flux, the accumulation of oxides can be significant.

Microstructure-based finite-difference analysis of the plastic flow in low-carbon steel

Despite extensive research, the question – what makes the fronts of plastic strain (e.g. Lüders bands) propagate or remain still has not been solved yet. Therefore, the problem is acute for modern solid mechanics and physics. In this paper, an analysis of low-carbon steel plastic flow is carried out both numerically and experimentally. A microstructure-based finite-difference analysis is employed to provide a deeper insight into the emerging features of plastic flow. Low-carbon polycrystalline steel is chosen as the basic material for this investigation. A hand-controlled iterative procedure based on the step-by-step packing method is utilized to design a representative volume element (RVE) of the low-carbon steel under study. The designed model represents a cluster of grains randomly distributed within the computational domain according to a certain law and randomly oriented with respect to the global coordinate system based on the results of EBSD study. A number of earlier reported models of plastic flow are combined and modified to study the yield plateau stage of the model samples. The mathematical model parameters are accurately calibrated against the experimental data using quite simple methods. The results of modeling satisfactorily meet the available experimental data and sufficiently complement them in terms of reproducing some regularities of plastic flow observed both at micro- and macrolevel. Relying on the numerical modeling data the conditions at the front of the Lüders bands are discussed, which shed light on a possible mechanism of propagation.

Development of grain-scale slip activity and lattice rotation fields in Inconel 718

Using a combination of in-situ high-resolution digital image correlation (HR-DIC), Heaviside-DIC method (H-DIC), and crystal plasticity finite element (CPFE), we investigate the evolution of intragranular lattice rotations and slip activity during monotonic and cyclic loading in a high performance, polycrystalline face centered cubic material. The CPFE employs a quasi-3D model microstructure, which is a highly resolved mirror representation of the experimental in-situ test sample. In agreement, the measurements and calculations reveal that most grains, regardless of their size and lattice orientation, develop intragranular lattice rotation gradients that span the grain. For a small cluster of grains on the deformed material, we perform HR-DIC analysis of slip lines to demonstrate agreement in the active slip systems and changes in this local slip activity across the individual grains. The combined analysis reveals that deforming grains are divided into sub-granular regions of uniform lattice rotation and these regions are most often associated with only one or two active slip systems. The gradient lines that divide them correspond to changes in the predominant slip system. The model is used to examine the evolution of intragranular lattice rotation in a single fully reversed tension-compression cycle. The calculations indicate that intragranular gradients intensify during the reverse loading path as nearest neighboring regions appear to shed lattice rotation, increasing the lattice rotation in some regions, while shutting down rotation in neighboring regions. These findings provide insight into the irreversible changes that develop within deforming grains at the scale of the grain, particularly the heterogeneous development of intragranular lattice rotation in early stages of deformation, which could serve as precursors to localization.

Extreme Clusters of Grains in Random Microstructures of Polycrystals

It was experimentally observed that in polycrystalline materials under low macro loading of the specimen the first sites of failure initiation take place in the specific clusters of few grains. In some grains of these extreme clusters, the local (meso-) strains and stresses are high enough to cause first damages or plastic slips. In the stochastic microstructure of polycrystals, the formation of an extreme cluster is random and rare. Nevertheless, they govern the failure process initiation and can severely affect the reliability of polycrystalline machine parts. It is time and resource consuming to search and investigate extreme clusters on the real specimens of polycrystalline materials experimentally. A theoretical tool is desirable. Here we present the powerful computational method to look for extreme clusters, to investigate their possible patterns, and to evaluate the absolute maximums of local strains/stresses that can be achieved in these clusters. The experimentally observed clusters consist of few (3-4) preferably oriented neighboring grains or even of one big supergrain. The strain and stress bursts arise due to an interaction of the grains. One can expect that in bigger clusters, larger local bursts of fields can be generated. We found the typical forms of the extreme clusters (small and big) in four different polycrystals with grains of a weak and strong anisotropy for the case of uniaxial tension. In all regarded cases, the extreme clusters have the forms of the symmetrical patterns. In big clusters of highly anisotropic grains, the maximum of mesostrain exceeds the macrostrain by several times. In clusters of weakly anisotropic grains, the local strain concentration is rather moderate (tens of percents).

Spontaneous formation of density waves in granular matter under swirling excitation

We study here the spontaneous clustering of a submonolayer of grains under horizontal circular shaking. The clustering of grains occurs when increasing the oscillation amplitude beyond a threshold. The dense area travels in a circular fashion at the driving frequency, which even exceeds the speed of driving. It turns out that the observed clustering is due to the formation of density waves. The analysis of a phenomenological model shows that the instability of the uniform density profile arises by increasing the oscillation amplitude and captures the non-monotonic dependence of the transition amplitude of the clustering on the global density of the system. Here, the key ingredient is that the velocity of individual grains increases with the local density. The interplay of the dissipative particle–particle interaction and frictional driving of the substrate results in this dependence, which is tested with discrete element method simulations.

Decoding Rocks: An Assessment of Geomaterial Microstructure Using X-ray Microtomography, Image Analysis and Multivariate Statistics.

An understanding of the microstructure of geomaterials such as rocks is fundamental in the evaluation of their functional properties, as well as the decryption of their geological history. We present a semi-automated statistical protocol for a complex 3D characterization of the microstructure of granular materials, including the clustering of grains and a description of their chemical composition, size, shape, and spatial properties with 44 unique parameters. The approach consists of an X-ray microtomographic image processing procedure, followed by measurements using image analysis and statistical multivariate analysis of its results utilizing freeware and widely available software. The statistical approach proposed was tested out on a sandstone sample with hidden and localized deformational microstructures. The grains were clustered into distinctive groups covering different compositional and geometrical features of the sample’s granular framework. The grains are pervasively and evenly distributed within the analysed sample. The spatial arrangement of grains in particular clusters is well organized and shows a directional trend referring to both microstructures. The methodological approach can be applied to any other rock type and enables the tracking of microstructural trends in grains arrangement.

Influence of Ce doping on morphology, crystallinity and photoelectrochemical charge transfer characteristics of TiO2 nanorod arrays grown on conductive glass substrate

Doping of rare earth elements into TiO2 nanorods allows tailoring of the electrical and optical properties, which in turn, modifies the photoelectrochemical behavior. This study presents hydrothermal synthesis of Ce doped TiO2 nanorod arrays on FTO coated glass substrate. XRD pattern confirms the rutile phase in both pristine and Ce doped samples; however, Ce doping results in an enhancement of peak intensity compared to that of pristine TiO2 nanorods. FESEM shows a significant change in the growth rate and the surface morphology of the nanorods with an apparent clustering of grains caused by Ce doping. HRTEM of the Ce doped sample shows regions of different crystallographic orientations. EDX data also confirms a uniform presence of Ce in the TiO2 nanorods. The optical absorption spectra show a slight redshift in the band gap from 3.08 eV for the pristine sample to 3.02 eV for the Ce doped nanorods that is attributed to the presence of shallow energy states within the band gap. Photoelectrochemical measurements indicate a negative shift in the flat-band potential from −0.80 V (for pristine) to −0.94 V (for Ce doped nanorods), resulting in a lower charge transfer resistance at the semiconductor/electrolyte interface, which is also corroborated by impedance spectroscopy. Although there is a reduction in the charge density, Ce doping facilitates better interfacial charge transport at the semiconductor/electrolyte interface.

Characterization of (Mg1.0Zn0.0)TiO3+4 wt%Bi2O3 Ceramics for Application as Resonator in Dielectric Resonator Oscillator Circuit

MgTiO3-based ceramics have potential applications in telecommunications systems at microwave frequencies, such as resonators in dielectric resonator oscillator (DRO) circuits. This paper reports the results of (Mg1.0Zn0.0)TiO3+4wt% Bi2O3 (abbreviated MZT0+4wt%Bi2O3) ceramic fabrication to assess its potential to be used as a resonator in the DRO circuit. We characterized its structure, microstructure, and bulk density. The addition of 4wt%Bi2O3 to MZT0 crystalline powder was carried out via ball-mill. The milled powder was compacted using a die press to obtain pellets. All pellets were sintered at 1100ºC for 4, 6, and 8 h. Ceramic structures of the 4 and 6 h holding time consists of MgTiO3 phase (94.33±2.68) and (95.34±1.95)% molar respectively, while the rest phase was TiO2. The 8-h ceramic structure comprises (96.11±2.94) % molar MgTiO3 accompanied by Mg2TiO5 and TiO2. The ceramics' microstructure consists of a cluster of grains with an average diameter of 1.32-2.24 μm and pores. Bulk density decreases with the increase of sintering holding time. The DRO characterization records a resonance signal each at 5.207, 5.005, and 5.121GHz with power approaching 0 dBm, suggesting that the MZT0+4wt%Bi2O3 ceramics can be used as a resonator in the DRO circuit working in microwave frequencies, especially at 5.0-5.2GHz.

Microstructural modeling of anisotropic plasticity in large scale additively manufactured 316L stainless steel

In this paper, the anisotropic mechanical response triggered by specific microstructures encountered in wire + arc additively manufactured 316L stainless steels is analyzed. For this purpose, a representative volume element is generated, with an internal geometry that is based on an average periodic fusion zone shape. The large columnar grain geometry with different preferred directions within a single fusion zone is reconstructed with an anisotropic Voronoi algorithm. Grain orientations are extracted from experimental data of different regions within a single sample. Crystal plasticity finite element simulations are performed to predict the macroscopic yield behavior under various loading angles. It is observed that the anisotropic response varies significantly within a single sample, which is essentially caused by differences in the texture. A spatial correlation between the orientation of a grain and its location within the fusion zone is identified, allowing to distinguish clusters of grains with a similar orientation. As a result, strain localizes in a global shear band across the entire height of the fusion zone, which prominently influences the macroscopic response. A comparison of the results relative to a standard isotropic Voronoi grain geometry shows that the elongated geometry of the grains does not influence the macroscopic yield behavior significantly. The local crystallographic orientations are dominating instead, whereby the correlation between location and orientation of grains has to be taken into account.

Optimal annealing of Al foil anode for prelithiation and full-cell cycling in Li-ion battery: The role of grain boundaries in lithiation/delithiation ductility

While self-supporting Al foil anode has high theoretical capacity and appropriate potential for Li-ion batteries, the poor initial Coulombic efficiency (ICE) retards its wide industrial applications, making prelithiation necessary. Herein, we develop a facile and efficient mechanical prelithiation (MP) approach suitable for mass production. Even though ICE was improved from 70% to 90% after MP, the cycling performance is still deficient, which we attribute to the insufficient density of grain boundaries that leads to poor lithiation/delithiation ductility (LDD), characterized by the rapid loss in electronic percolation across the foil. As a classic strategy in metallurgy to tune the grain boundaries, thermal annealing and recrystallization is further exploited to optimize the LDD of Al foil. For standard Al foil, whose grain size is big with lots of dislocations inside, MP followed by electrochemical cycling causes cracking, electrolyte infiltration and SEI formation. Its electronic percolation (damage) is monitored in real time, and is found to decay rapidly as the insulating SEI blocked all the electron transport paths of one grain (or a cluster of grains). But if MP takes place after annealing standard Al foil at 300 °C for 15min, the dislocations recombined to achieve refined grains whose sharp GB network can slide effectively to relieve stress buildup due to phase transitions and suppress deep crack development, and the prelithiated foil achieved superior electrochemical performance, with significant life extension in the in-plane electronic conductance. However, interestingly, upon further increase in the annealing temperature, as the grain size turns bigger, the electrochemical performance of prelithiated foil deteriorates. Based on the comparison of the microstructures and electrochemical performance at different thermal annealing conditions, we found that the GB density before MP plays an essential role in the stress relief and keeping electronic percolation during cycling. Our optimized prelithiated Al foil maintains 80% capacity retention after 100 cycles in LiFePO4//LiAly full cell with 1.8 × excess lithium. It cycles significantly better than pure LiBCC foil of equal thickness (65 μm), especially in lean-electrolyte condition, suggesting such safe, cheap and high energy density metallic foil anodes deserve comparable attention as pure lithium metal anode.

Scaling Law for Cracking in Shrinkable Granular Packings.

Hydrated granular packings often crack into discrete clusters of grains when dried. Despite its ubiquity, an accurate prediction of cracking remains elusive. Here, we elucidate the previously overlooked role of individual grain shrinkage-a feature common to many materials-in determining crack patterning using both experiments and simulations. By extending classical Griffith crack theory, we obtain a scaling law that quantifies how cluster size depends on the interplay between grain shrinkage, stiffness, and size-applicable to a diverse array of shrinkable granular packings.

Inhomogeneities and Extreme Fluctuations of Strains in Grains of Polycrystalline Materials

Inhomogeneity of strains in individual grains are calculated using the field-theoretical approach in the mechanics of polycrystalline materials. It is shown that the microstructure surrounding the grain strongly influences the amplitude of the non-uniformity of strains in the grain. In the random microstructure of a polycrystal, there are specific clusters of grains in which very large strain fluctuations are realized. The strains in these clusters exceed macrostrains several times. The patterns of such extreme clusters are presented. Extreme strain fluctuations in bulk grains exceed fluctuations in surface grains by 40%. This may be one of the reasons for the movement of sites of damage initiation in gygacycle fatigue mode from the surface of a polycrystalline sample into the bulk.

Grain growth enhancing through preheating treatment of a sputtered stacked metallic precursor for Cu(In, Al)Se2 thin film solar cells application

The influence of preheating treatment of a sputtered stacked metallic precursor on structural property of the CuInAl precursor and detailed structural, morphological and optical analyses as well as in the finally obtained Cu(In, Al)Se2 (CIAS) thin film solar cell device characterization are investigated systematically. These results indicate that this preheating process exhibits a strong beneficial impact on crystal growth and eventually produces a substantial improvement in photovoltaic properties. However, further increase of the preheating temperature, despite enhancing grain growth, clustering of grains loosely distribute on the surface of the CIAS thin film, forming a rather rough morphology. Thus, an accurate control of the preheating temperature during grain growth process may be necessary. Here, when optimizing the preheating temperature to 300 °C, the largest grain size and the best photovoltaic performance achieved. The findings provide an important insight into the understanding of fundamental research of current chalcopyrite solar cell application.