Material Innovation: Scientific Researchers Have Made Progress In Fiber Research Reinforcement Materials In Martian Soil

Mars is considered to be the most suitable planet for human migration in the solar system besides the Earth, and also the starting point for human exploration of the vast universe. In recent years, the construction of the Mars base has attracted attention. The surface of Mars is covered with Martian soil. In situ utilization of Martian resources can reduce the construction cost of the base and improve the sustainability of human survival on Mars. Composite material is a binary or multi-component hybrid system composed of matrix and reinforcement. The composite materials learn from each other in performance and produce synergistic effect, which makes the composite material superior to the original composite material in comprehensive performance to meet different requirements. Therefore, if Martian resources can be used in situ to obtain matrix and reinforcement and make them into composite materials, it is expected to reduce the dependence of Martian base construction and operation and maintenance process on Earth resources.

Recently, the Xinjiang Institute of Physical and Chemical Technology and the Institute of Geochemistry of the Chinese Academy of Sciences, together with the Chinese University of Hong Kong (Shenzhen) and others, discussed the feasibility of preparing continuous fibers from Martian soil and using them to build the Martian base, starting from the demand for high-performance reinforcement materials in the construction of the Martian base. It is found that Martian soil and earth basalt have similar chemical composition, mineral phase composition and melting behavior. Experiments show that the simulated Martian soil It is completely melted at ℃, and there is no obvious crystal precipitation during melting cooling process, and the melt is transformed into amorphous glass after quenching. Guided by this experimental result, the researchers obtained continuous Martian soil fibers at different fiber forming speeds by melt pull method. The research shows that the average diameter of the obtained fiber is 9.7-13.9 μm， The maximum tensile strength of monofilament is 1320 MPa, and the maximum tensile modulus is 99 GPa。 At the same time, it was found that the tensile strength and Young's modulus of the fiber decreased with the increase of the fiber forming speed. This may be due to the influence of fiber forming speed on the aggregation structure of atoms in the fiber.

In Martian soil fiber, Si is the main element, and the content exceeds 45 Wt%. Si atoms will form a tetrahedron structure with O atoms, and then form network units in the fiber. One O atom linked to two Si atoms is bridge oxygen, otherwise it is non bridge oxygen. In general, the more the number of bridging oxygen bonds in silicate system, the higher the degree of polymerization of the network formed by Si atoms. The researchers used Raman spectrum and Gaussian peak fitting research to confirm that the degree of network polymerization of Martian soil fiber decreases with the increase of fiber forming speed, specifically, the peak area of silicon oxygen tetrahedron containing three bridge oxygen in Raman spectrum gradually decreases. Therefore, this study proves that the Martian soil fiber prepared at a lower fiber forming speed has a more compact atomic structure, which makes it easier to resist external damage, and thus has better mechanical properties.

Further, the researchers analyzed the influence of the above factors on the fiber forming process and properties in combination with the environmental conditions of Mars low gravity and special atmosphere (low pressure and inert atmosphere).

The research shows that continuous and diameter controllable fiber materials can be obtained from Martian soil. At the same time, the obtained fiber is expected to be prepared by composite technology, which has application value for the construction of Martian base in situ using Martian soil.

Relevant research results were published in iScience. The research work was supported by the National Natural Science Foundation of China, relevant projects of the Chinese Academy of Sciences, and the "Tianshan Talent" Training Program of Xinjiang Uygur Autonomous Region.