PSI - Issue 77

Fabian Jung et al. / Procedia Structural Integrity 77 (2026) 308–315 Fabian Jung / Structural Integrity Procedia 00 (2026) 000–000

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An evaluation was conducted to assess the oxidation behavior of MAXCarbon in comparison with standard carbon nonwovens. While unmodified carbon fibers fully oxidized at temperatures below 700°C within 10 minutes, MAXCarbon nonwoven material maintained structural integrity beyond 1300°C. In-situ monitoring using a heating microscope revealed gradual surface changes but no catastrophic degradation of the MAXCarbon samples, indicating effective protection by the Ti₃SiC₂ boundary layer. Preliminary findings indicate a substantial enhancement in thermal stability and oxidation resistance. 4.3. Mechanical Performance Single filament tensile tests revealed an average tensile strength of 2206.69 MPa for the MAXCarbon hybrid fibers. This corresponds to approximately 85% of the strength of SiC fibers and ~55% of the original carbon fibers (~4000 MPa). Subsequent to the formation of Ti3SiC2, there was an increase in the fiber diameter from 7 µm to 8.022 µm, which led to a reduction in the load-bearing cross-section of the carbon core to approximately 6.277 µm. When normalized to this effective carbon core diameter, the tensile strength of MAXCarbon was calculated to be 2460.86 MPa, which is approximately 62% of the strength of the initial carbon fibers. This result indicates that the strength of the MAXCarbon fibers is approximately 58% greater than that of conventional SiC fibers, thereby underscoring the potential of MAXCarbon as a hybrid reinforcement material. Comparative benchmarks are listed in Table 4.1, which highlights the performance trade-offs relative to established high-performance fibres.

Table 4.1:

Comparison of the material characteristics of MAXCarbon and established high-performance fibres

Material

Type

Tensile Strength [MPa]

norm.

Modulus

Elongation at Break [%]

Density

Single Fil. Ø

Tensile Strength* [MPa]

[GPa] 207,62

[g/cm³]

[µm] 8,022

Ti 3 SiC 2 -CF Hybrid

MAXCarbon

2206,69

2460,86

1,04 ±0,15

1,77 2,5 -

±400,68

±446,83

±12,4

±0,705

SiCO

CG Nicalon (NGS) Hi-Nicalon (NGS)

2600

188

1500,00

1

14

3000

210

2,65

SiC

2500

1286,76

250

1

2,65

13,6

SiC

Hi-Nicalon Type S (NGS)

2550

1463,11

340

0,6

2,91

12,2

SiC

Sylramic (COI Ceramics)

2758

1930,60

310

0,5

2,95

10

CF

Sigrafil C T50 4.0/240 (SGL)

4000

4000,00

240

1,7

1,8

7

CF

Tenax-E

HTA40

4100

4100,00

240

1,7

1,77

7

E13 (Toho)

* Tensile strength normalized to 7 µm CF-Ø The discussion of the results suggests that the reduction in tensile strength cannot be solely attributed to the decrease in effective cross-sectional area. The observed strength loss is likely attributable to additional factors, including residual stresses, processing-induced defects, and the absence of a protective sizing. The Ti 3 SiC 2 layer, being comparatively soft, provides negligible direct contribution to tensile load capacity; however, it serves a vital protective function against oxidation and chemical degradation. Further optimization of process parameters and protective sizing strategies is imperative to mitigate strength reduction.