Subsequent Extrusion Research Articles

Effect of pressure-free heating curing time on bending property of 2D T700/E44 composites prepared by ICM

Six kinds of 2D T700/E44 composites with pressure-free curing times of 40 min, 60 min, 80 min, 100 min, 120 min and 140 min are prepared by improved compression molding process (ICM). The macroscopic morphology of the composites is satisfactory. The microstructure observation and bending performance tests show that composites have poor infiltration effect. When the pressure-free curing time is less than 80 min, defects are easy to occur such as insufficient infiltration and voids. Bad infiltration and void defects will lead to poor continuity of carbon fiber and resin, and their bending fracture will also be unreasonable, so the bending strength of composite at 40 min is 275 MPa. The infiltration effect is gradually improved with the increase of pressure-free heating curing time. However, when the pressure-free heating curing time reaches 120 min or more, the infiltration effect of the composites is deteriorated, and this is due to excessive infiltration time and extrusion force in subsequent heating extrusion infiltration process. Defects such as fiber aggregation and uneven infiltration are prone to occur, and bending strength of composites reduces to 380 MPa. When the pressure-free curing time is 100 min, the infiltration effect of the prepared composite is satisfactory, and the imbalanced infiltration and hole defects are effectively eliminated. The bending fracture of composite material is uneven, carbon fibers and resin play the roles of reinforcement and transferring loads effectively respectively, so the bending strength of the prepared 2D T700/E44 composite reaches 730 MPa.

Three-Dimensional Printing of Abrasive, Hard, and Thermally Conductive Synthetic Microdiamond–Polymer Composite Using Low-Cost Fused Deposition Modeling Printer

A relative lack of printable materials with tailored functional properties limits the applicability of three-dimensional (3D) printing. In this work, a diamond-acrylonitrile butadiene styrene (ABS) composite filament for use in 3D printing was created through incorporation of high-pressure and high-temperature (HPHT) synthetic microdiamonds as a filler. Homogenously distributed diamond composite filaments, containing either 37.5 or 60 wt % microdiamonds, were formed through preblending the diamond powder with ABS, followed by subsequent multiple fiber extrusions. The thermal conductivity of the ABS base material increased from 0.17 to 0.94 W/(m·K), more than five-fold following incorporation of the microdiamonds. The elastic modulus for the 60 wt % microdiamond containing composite material increased by 41.9% with respect to pure ABS, from 1050 to 1490 MPa. The hydrophilicity also increased by 32%. A low-cost fused deposition modeling printer was customized to handle the highly abrasive composite filament by replacing the conventional (stainless-steel) filament feeding gear with a harder titanium gear. To demonstrate improved thermal performance of 3D printed devices using the new composite filament, a number of composite heat sinks were printed and characterized. Heat dissipation measurements demonstrated that 3D printed heat sinks containing 60 wt % diamond increased the thermal dissipation by 42%.

Microstructure evolution and high-temperature tensile behavior of the powder extruded 2.5 vol% TiBw/TA15 composites

In this paper, 2.5 vol% TiBw/TA15 composites were fabricated by low-energy milling and subsequent powder extrusion. After low-energy milling process, the fine TiB2 powders were adhered on the surface of the spherical TA15 powders. Next, the blended powders were extruded at 1100 °C with extrusion ratio of 10:1. The Widmanstatten α + β microstructure with thickness of 550–620 nm in α phase was obtained and the strong (0001)α//ED and (101)α//ED texture was formed after powder extrusion. The TiB whiskers (TiBw) twisted along the extrusion direction and led to the ‘wall’ structure. High-temperature tensile behavior of this studied composites was investigated at 800–950 °C with strain rate of 0.001–0.1 s−1. According to the stress-strain curves, the activation energy (Q) was calculated to be 325 kJ mol−1, higher than the TA15 matrix, which is due to the combined effect of phase morphology, extrusion texture and TiBw reinforcements. In addition, the tensile strain has effect on microstructure evolution. Static spheroidizing has been processed in the grip area of tensile sample. As the tensile strain increased, the volume fraction of and the average grain size α phase decreased. Moreover, voids nearby the TiBw reinforcements were observed due to the incoordination deformation between TiBw and TA15 matrix.

Enhanced combination of strength and ductility in ultrafine-grained aluminum composites reinforced with high content intragranular nanoparticles

Simultaneous enhancement of the strength and ductility in metal-matrix nanocomposites with high content nano-reinforcements is crucial for the development of novel composite materials. Here SiC/Al nanocomposites with ultrafine Al grains and intragranular 10 vol% SiC nanoparticle were prepared by mechanical alloying and hot pressure sintering followed by hot extrusion. The results show that nanocrystalline Al grains and uniformly distributed SiC nanoparticles (SiCnp) in the composite powders are obtained after ball-milling. The prior particle boundary (PPB) in the composite powders cannot be fully removed by sintering at 580 °C under 20 MPa, but can be eliminated by subsequent hot extrusion at 450 °C with a ratio 25:1. The extruded nanocomposites possess ultrafine Al grains with diameter 320 nm and intragranular SiCnp created by the dynamic recrystallizations (DRX). Such optimal microstructure favors a significant improvement of 284% in yield strength (YS) and 259% in ultimate tensile strength (UTS) compared with monolithic Al, and more interestingly, maintains an elongation up to 12% due to the homogeneous nanoparticles in fine Al grains. Theoretical analysis shows that the dominant strengthening factor is Orowan strengthening related to the high content intragranular SiCnp, with second factor grain boundary strengthening due to ultrafine Al grains.

Characterization of Ni3Al Alloy Fabricated by Thermal Explosion and Hot Extrusion Process

In the present paper, the trace B doped Ni3Al alloy was prepared by the thermal explosion and hot extrusion (TH/HE) technique. Its micro-structure characterization and mechanical properties were carried out by OM, XRD, TEM, compression and micro-hardness tests. Micro-structure examinations exhibit that the TH/HE technology has transformed the powders into Ni3Al alloy with less porosity. In the synthesized part, coarse and ultrafine Ni3Al grains comprise the dual-scale grain structure with segregated Al2O3 particles along grain boundary. TEM observations reveal that γ-Ni, Al2O3 and Ni3Al phases coexist in the synthesized part. Moreover, the Al2O3 particles in the synthesized part have α-Al2O3 and γ-Al2O3 two crystal structures. In addition, there is a transition region along the interface of Al2O3 and Ni3Al grain. The subsequent hot extrusion optimize the micro-structure of the extruded part by homogenizing the Ni3Al grain, uniformly distributing Al2O3 and generating massive substructures. The great deformation results in the pile-up of dislocations, intersected dislocations and substructures. Moreover, the movement of dislocation promotes the formation of micro-twinning in the Ni3Al grain, which is accompanied with the stacking faults and nano-structure. The mechanical properties exhibit that the micro-structure optimization caused by the TE/HE technology improves the compressive ductility and strength of the Ni3Al alloy obviously. DOI: http://dx.doi.org/10.5755/j01.ms.24.4.19460

The influence of forging and extrusion on the microstructure and martensitic transformation in Ni-Mn-Ga alloys

The work presents the comparative analysis of the microstructure and character of martensitic transformation in Heusler Ni-Mn-Ga alloys subjected to plastic deformation by forging and complex treatment by forging with subsequent extrusion. It is shown that the treatment by forging leads to the formation of a bimodal structure with large grains of several micrometres surrounded by a fine-grained structure. After a complex treatment, a bimodal structure is also observed. But the volume fraction of the fine-grained structure is larger than in the previous case. Analysis of the martensite transformation temperature shows that thermomechanical treatment by both methods leads to a slight shift in the martensite transformation temperature to the low temperature region.

Microstructures and mechanical properties of ultrafine-grained Ti/AZ31 magnesium matrix composite prepared by powder metallurgy

The microstructure of ultrafine grain for magnesium alloys can result in drastic enhancement in their room temperature strength, but the issue of low strength at elevated temperature becomes more serious as well due to grain boundary slide. Here ultrafine-grained Ti/AZ31 magnesium matrix composites with high strength at both room and elevated temperature were prepared by vacuum hot pressing and subsequent hot extrusion. The microstructure of the composite samples before and after consolidation processing was characterized, and the mechanical properties of the as-consolidated bulk samples were measured at room and elevated temperatures. The results indicate that after extrusion ultrafine-grained magnesium alloys were obtained and Ti particulates with particulate size of ∼310 nm disperse in Mg matrix. The magnesium grain of AZ31-15at.%Ti grows from 66 nm to 800 nm. Meanwhile, the relative densities of Ti/AZ31 composites are higher than 99%. The yield strength (YS) of extruded AZ31-15at.%Ti composite at room temperature is 341 MPa, being 2.4 times higher than original AZ31 alloy. Theoretical estimation shows that remarkably enhanced room-temperature mechanical strength attributes to grain boundary strengthening with the contribution ratio of 74%. In addition, the peak stress of extruded AZ31-15at.%Ti composite at 573 K is 82 MPa and ultrafine Ti dispersions are responsible for the enhanced strength.

Preparation and characterization of biodegradable Mg-Zn-Ca/MgO nanocomposites for biomedical applications

In order to improve the corrosion resistance and mechanical properties of magnesium alloys for biomedical implant applications, novel biodegradable Mg-3Zn-0.2Ca (wt%) matrix composites, reinforced by adding various contents of MgO nanoparticles (0.1, 0.2, 0.3, 0.5 wt%), were devised and prepared using high shear melt conditioning. An optimum solution treatment (450 °C, 48 h) and subsequent hot extrusion was carried out to produce the Mg-3Zn-0.2Ca/MgO composites. It was found that the as-extruded composite exhibited a fine grain structure with relatively uniformly distributed MgO particles. The orientation relationships (ORs) of (1 1 1)MgO ~ 2.62° from (0 0 0 2)α-Mg and [0 −1 1]MgO // [2 −1 −1 0]α-Mg, were observed between the MgO particles and the α-Mg matrix via high resolution transmission electron microscopy (HRTEM) investigation and fast Fourier transform (FFT) pattern analysis, verifying the excellent interfacial bonding between the phases. Additionally, a substantial reduction in the secondary phase content was found in the solution treated sample. In vitro immersion, electrochemical, and mechanical tensile tests were used to characterize the corrosion behavior and mechanical properties. The ultimate tensile strength (UTS) increased to 329.03 ± 2.01 MPa and the yield tensile strength (YTS) increased by 22.81% with 0.5 wt% MgO loading, while the ductility did not substantially deteriorate. The polarization resistance (Rp) of the composite was shown to increase from 0.95 kΩ cm2 to 2.02 kΩ cm2 with the addition of 0.2 wt% MgO. With increasing MgO content, agglomeration of the MgO particles was detected in the analyzed composite, resulting in decreased ductility and the occurrence of pitting corrosion.

Role of Al content on the microstructure, texture and mechanical properties of Mg-3.5Ca based alloys

Effects of Al addition (0.0, 0.5, 3.0, 7.2 wt%) on microstructure, texture and mechanical properties of Mg-3.5Ca based alloys were investigated. Our results revealed that the addition of Al to the as-cast Mg-3.5Ca alloy resulted in the transformation of precipitated secondary phase from Mg2Ca to (Mg, Al)2Ca, Al2Ca and even Mg17Al12 phase. Moreover, the as-cast microstructure evolution influenced dynamic recrystallization and texture formation in the subsequent extrusion process. As Al content increased from 0.0 to 7.2 wt%, the elongation to fracture (EL) of as-extruded Mg-3.5Ca alloy was monotonously increased from 1.9% to 9.8% in tension, while counterparts were changeless in compression. As-extruded Mg-3.5Ca-3.0Al alloy showed higher yield and ultimate strength increased by about 42.2 MPa and 71.4 MPa than those of extruded Mg-3.5Ca alloy in tension, respectively. Moreover, when Al addition was up to 7.2 wt%, both tensile yield strength and ultimate tensile strength were in steep decline. The effects of Al addition on compressive mechanical properties (compressive yield strength and ultimate compressive strength) were similar to that in tension. Especially, significantly deteriorated tension-compression asymmetry (TCA) of Mg-3.5Ca-7.2Al alloy was ascribed to grain coarsening and secondary phase transformation. Besides, Al addition also had a significant impact on the hardening capacity (Hc) and strain hardening behavior of Mg-3.5Ca alloy. In particular, as 7.2 wt% Al was added, the hardening capacity of the Mg-3.5Ca alloy was significantly increased from 0.09 to 0.56 in tension. As a result, proper Al addition to Mg-3.5Ca alloy could improve the comprehensive mechanical performance, whereas excessive Al addition not only significantly decreased the strength, but also deteriorated the TCA performance.

Effect of Solidification Cooling Rate on Microstructure and Mechanical Properties of an Extruded Mg-Zn-Y Alloy

The Effect of the solidification conditions and subsequent extrusion of a Mg-3.0Zn-0.5Y (at. %) alloy containing quasicrystalline icosahedral (i-) phase was studied. Solidification was carried out by three methods using a chill casting mold, a conventional steel mold and a water-cooled mold. Subsequently, castings were extruded in the temperature range of 235–270 ∘ C at an extrusion ratio of 25:1. The solidification molds showed different characteristics. The water-cooled mold was most effective in cooling through the walls, but least effective at the center of the mold. The conventional cast mold was the most effective in cooling at the mold center. All the castings had an interdendritic eutectic structure of the i-phase, and a supersaturation of the matrix in zinc. As a result, all the extrusions had similar grain size close to 1 μ m and very fine nano-size precipitation. Yield strengths in tension were in the range of 376 and 404 MPa, and from 300 to 330 MPa in compression. All elongations to fracture were about 13%. It is concluded that supersaturation of the matrix during solidification is the main factor, resulting in the dynamic precipitation of very fine precipitates and fine grain size during extrusion.

Signature Arsenic Detoxification Pathways in Halomonas sp. Strain GFAJ-1.

ABSTRACTSince the original report that Halomonas sp. strain GFAJ-1 was capable of using arsenic instead of phosphorus to sustain growth, additional studies have been conducted, and GFAJ-1 is now considered a highly arsenic-resistant but phosphorus-dependent bacterium. However, the mechanisms supporting the extreme arsenic resistance of the GFAJ-1 strain remain unknown. In this study, we show that GFAJ-1 has multiple distinct arsenic resistance mechanisms. It lacks the genes to reduce arsenate, which is the essential step in the well-characterized resistance mechanism of arsenate reduction coupled to arsenite extrusion. Instead, GFAJ-1 has two arsenic resistance operons, arsH1-acr3-2-arsH2 and mfs1-mfs2-gapdh, enabling tolerance to high levels of arsenate. mfs2 and gapdh encode proteins homologous to Pseudomonas aeruginosa ArsJ and glyceraldehyde-3-phosphate dehydrogenase (GAPDH), respectively, which constitute the equivalent of an As(V) efflux system to catalyze the transformation of inorganic arsenate to pentavalent organoarsenical 1-arseno-3-phosphoglycerate and its subsequent extrusion. Surprisingly, the arsH1-acr3-2-arsH2 operon seems to consist of typical arsenite resistance genes, but this operon is sufficient to confer both arsenite and arsenate resistance on Escherichia coli AW3110 even in the absence of arsenate reductase, suggesting a novel pathway of arsenic detoxification. The simultaneous occurrence of these two unusual detoxification mechanisms enables the adaptation of strain GFAJ-1 to the particularly arsenic-rich environment of Mono Lake.

Nanostructured Composite Materials Based on Al–Mg Alloy Modified with Fullerene C60

Nanostructured composite materials (NCMs) based on Al–Mg alloy AMg6 (1560) modified with fullerene C60 are obtained by milling of initial materials in a high-energy planetary ball mill and the subsequent hot extrusion of powder mixtures. The structure, phase composition, and physical and mechanical properties of NCMs obtained are studied. It is shown that introduction of 0.3 wt % of fullerene C60 into NCMs prevents agglomeration of the particles during milling, intensifies the particle size reduction, and makes it possible to obtain an average aluminum crystallite size less than 50 nm. After consolidation of the powder mixtures by direct hot extrusion, the obtained materials demonstrate an increase in tensile strength up to 820 MPa and in bending strength up to 1.11 GPa. In this case, the density of NCMs is 2.61 g/cm3, which provides a value of the specific strength on the level of titanium alloys and fiberglass.

High-strength Mg-6Zn-1Y-1Ca (wt%) alloy containing quasicrystalline I-phase processed by a powder metallurgy route

A high-strength Mg-6Zn-1Y-1Ca (wt%) alloy has been processed by a powder metallurgy route. Rapidly solidified powders with a particle size below 100µm were used as a way for preventing formation of ternary MgZnCa compounds during subsequent extrusion at 250°C. The microstructure of the extruded alloy consists of an ultrafine-grain magnesium matrix, with an average grain size of 444nm, embedding a high volume fraction of fine I-phase particles aligned along the extrusion direction. The alloy combines an excellent ductility (14% of elongation to failure) with a high strength (ultimate strength of 469MPa and yield stress of 461MPa) at room temperature, mainly due to grain size refinement (around 70% of the yield stress). The strength is kept high up to 150°C (yield stress of 279MPa). Above this temperature, the mechanical strength falls to very low values but the ability to deform plastically is considerably enhanced, exhibiting superplastic behaviour from 200 to 350°C, with a maximum elongation of 477% at 350°C.

High temperature tensile properties of hypereutectic Al-25Si based alloy

The high temperature tensile deformation of a hypereutectic Al-25Si based alloy fabricated by spray forming and subsequent hot extrusion was investigated. Tensile tests were conducted at various temperatures and strain rates. It was revealed that the ductility of the alloy is sensitive to both the test temperature and strain rate. At a given strain rate, the peak value of elongation was obtained at 500 °C. At 490 °C and above, the peak value of elongation was observed at a strain rate of 1.0 × 10-2 s-1, although the elongation increased with decreasing strain rate at 460 °C and below. The high elongation was exhibited when a high strain rate sensitivity index (m value) was attained and a liquid phase existed during deformation. The liquid phase appeared as a filament-like structure which is aligned with the tensile direction on the fracture surface of the tensile deformed specimen. A higher elongation (>35%) was obtained when the volume fraction of the liquid phase was 0.7%-1.7%. The maximum elongation of 75% was achieved when the volume fraction of the liquid phase was about 1%. The transition of the activation energy was observed at 430 °C when incipient melting occurred.

Microstructure evolution and mechanical properties of as-extruded Mg-Gd-Y-Zr alloy with Zn and Nd additions

The microstructure evolution and mechanical properties of as-extruded Mg-11.5Gd-4.5Y-0.3Zr (wt%) alloy with Zn and Nd additions were investigated. The addition of Zn inhibits the dynamic recrystallization (DRX) due to the presence of the long-period stacking ordered (LPSO) phase. The addition of Nd promotes the precipitation of the Mg5RE (RE: rare earth) phase. The existence of the densely distributed Mg5RE phase before hot extrusion promotes the DRX in subsequent hot extrusion process and leads to grain refinement. The increase in the number of Mg5RE phase particles degrades the mechanical properties of the resultant alloy. After hot extrusion, the studied alloys exhibit a bimodal microstructure consisting of fine dynamic recrystallized (DRXed) grains of several microns and strongly textured course un-DRXed grains. The as-extruded Mg-11.5Gd-4.5Y-1.5Zn-0.3Zr alloy exhibits an excellent balance of strength and ductility (tensile yield strength of 371 ± 3.0MPa and elongation of 7.2 ± 0.8%). The alloy strengthening is attributed to the bimodal microstructure, the Mg5RE and LPSO phases, and the basal texture. The tensile yield strength of the as-extruded Mg-11.5Gd-4.5Y-1.5Zn-0.3Zr alloy can be further increased to 425 ± 2.5MPa by precipitation hardening with the T5 treatment.

Microstructure and mechanical properties of a hot-extruded Al-based composite reinforced with core\u2013shell-structured Ti/Al3Ti

An Al-based composite reinforced with core–shell-structured Ti/Al3Ti was fabricated through a powder metallurgy route followed by hot extrusion and was found to exhibit promising mechanical properties. The ultimate tensile strength and elongation of the composite sintered at 620°C for 5 h and extruded at a mass ratio of 12.75:1 reached 304 MPa and 14%, respectively, and its compressive deformation reached 60%. The promising mechanical properties are due to the core–shell-structured reinforcement, which is mainly composed of Al3Ti and Ti and is bonded strongly with the Al matrix, and to the reduced crack sensitivity of Al3Ti. The refined grains after hot extrusion also contribute to the mechanical properties of this composite. The mechanical properties might be further improved through regulating the relative thickness of Al–Ti intermetallics and Ti metal layers by adjusting the sintering time and the subsequent extrusion process.

Novel bio-nanocomposite hybrids made from polylactide/nanoclay nanocomposites and short flax fibers

This article aims to formulations and properties of novel hybrid biomaterials containing unique four-phase combinations of polylactide (PLA), nanoclays, flax fibers, and coupling agents. A PLA-grafted maleic anhydride (PLA- g-MA) masterbatch containing 10 wt% PLA- g-MA was obtained by reactive extrusion and was further used, after dilution, as a coupling agent. In addition, three PLA masterbatches containing 10 wt% of three different grades of nanoclays, one untreated nanoclay and two organonanoclays, were also compounded. In a subsequent extrusion step, the nanoclay masterbatches were diluted in PLA down to 4 and 2 wt% while simultaneously incorporating in each one 20 wt% of short flax fibers. Those bio-nanocomposites were compounded without and with an equivalent content of PLA- g-MA, that is, with 4 and 2 wt%, respectively, through the dilution of 10 wt% PLA- g-MA masterbatch. The effects of the nanoclay chemistries, PLA- g-MA, and of flax fibers presence on the properties of bio-nanocomposite hybrid materials were investigated. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, rheology, mechanical properties (tension, flexural, and Izod impact), and reprocess ability tests were used to characterize the bio-nanocomposite hybrid materials. In a second step, PLA- g-MA was replaced by an epoxy/styrene/acrylic copolymer for comparison purpose of their respective effect in bio-nanocomposite performances. Mechanical properties of bio-nanocomposites containing the second coupling agent were also evaluated. The effect of the epoxy/styrene/acrylic copolymer is discussed in comparison with the effect of PLA- g-MA.

Impact of fermentation and extrusion processing on physicochemical, sensory and bioactive properties of rice-black gram mixed flour

Current study details about the impact of solid state fermentation and subsequent extrusion on the physicochemical, sensory and bioactive properties of the rice-black gram dough. Influence of the solid-state fermentation was evaluated, at three levels of yeast concentration (1–3%), sugar (4–8%) and fermentation time (2–6 h). Fermentation resulted in decreased pH and residual sugar, from 6.38 to 5.41 and 1.07 to 0.69%, respectively, whereas the titratable acidity was increased from 0.86 to 1.79%, after 6 h of fermentation. Moreover, solid state fermentation for 6 h leads to increased total phenolic content, antioxidant activity and protein content from 29.80 to 44.12 mg GAE/100 g, 3.38–5.10 mg GAE/100 g and 10.36–13.65%, respectively. FTIR analysis showed decreased crystallinity up on fermentation. Subsequently, dough fermented for 6 h with 3% yeast and 4% sugar (optimized condition) was considered for the extrusion processing, which leads to increased phenolic content and antioxidant activity up to 77.3 mg GAE/100 g, and 11.39 mg GAE/100 g, respectively. Expansion ratio, bulk density, water solubility and water absorption index were determined for product characterization. Furthermore, extrudate prepared from the fermented flour had slightly higher acceptability (mean score: 4.12) than the unfermented counter part (mean score: 3.75) out of 5.

Effect of Al2O3 Nanoparticles as Reinforcement on the Tensile Behavior of Al-12Si Composites

Al2O3 nanoparticle-reinforced Al-12Si matrix composites were successfully fabricated by hot pressing and subsequent hot extrusion. The influence of weight fraction of Al2O3 particles on the microstructure, mechanical properties, and the corresponding strengthening mechanisms were investigated in detail. The Al2O3 particles are uniformly distributed in the matrix, when 2 and 5 wt. % of Al2O3 particles were added to the Al-12Si matrix. Significant agglomeration can be found in composites with 10 wt. % addition of Al2O3 nanoparticles. The maximum hardness, the yield strength, and tensile strength were obtained for the composite with 5 wt. % Al2O3 addition, which showed an increase of about ~11%, 23%, and 26%, respectively, compared with the Al-12Si matrix. Meanwhile, the elongation increased to about ~30%. The contribution of different mechanisms including Orowan strengthening, thermal mismatch strengthening, and load transfer strengthening were analyzed. It was shown that the thermal mismatch strengthening has a more significant contribution to strengthening these composites than the Orowan and load transfer strengthening mechanisms.

The effects of the interface on microstructure and rheo-mechanical properties of polyamide 6/cellulose nanocrystal nanocomposites prepared by in-situ ring-opening polymerization and subsequent melt extrusion

Polyamide 6 (PA6) nanocomposites containing cellulose nanocrystals (CNCs) were prepared via a multi-step process consisting of in-situ anionic ring-opening polymerization and subsequent melt extrusion. The effect of surface modification of the CNCs with aminopropyl triethoxysilane (APS) was studied in detail using microscopic, mechanical and rheological techniques and compared with that of the neat CNC nanocomposites. Solid-state 29Si NMR analysis was used to confirm the interfacial bond formation between the PA6 matrix and surface modified CNCs. SEM images showed that upon surface modification, the morphology of CNCs within the matrix transformed from a fibrillar structure towards more individually dispersed nanocrystals with enhanced dispersion and higher interfacial area. The matrix-particle interphase was further investigated using quantitative nanomechanical mapping (QNM) to study the role of interfacial modification on thickness of interphase and development of a broader modulus gradient across the interface. The quality of dispersion and development of the rigid interfacial layer in the modified system resulted in significant improvement in solid-state mechanical properties of the nanocomposites. In addition, melt rheological studies showed significant improvements of melt elasticity and strength in shear and elongational flow in the nanocomposites systems.