China’s Super Tungsten Alloy and Prof. Fan Jinglian

Tungsten is a high melting point rare metal or refractory rare metal in the field of metallurgy and metal materials. It is an important strategic reserve resource for the country. Tungsten is one of the most important functional materials in modern industrial, national defense and high-tech applications. The hard alloy made of tungsten is known as “industrial teeth”. Although China's current strength in the field of high-end alloys still lags behind that of developed countries, after years of hard work, R&D strength has been continuously improved. This article mainly introduces a female scholar who has been studying tungsten tungsten alloy for more than 20 years, Professor Fan Jinglian, director of the Institute of Refractory Metals and Cemented Carbides, Institute of Powder Metallurgy, Central South University.

On May 10, 2018, the third edition of Hunan Daily, "Fan Nano" and her high-end new materials, the media introduced Professor Fan Jinglian. For more than 20 years, Fan Jinglian has continuously overcome world-class technical difficulties, developed micro-nano composite lightweight refractory metal-based composite materials, high-performance tungsten-based composite materials, and successfully realized industrialization. The materials are applied to China's aerospace and aircraft. field.

The reason why cemented carbide is "hard bone" is that China has started tungsten-based alloy research since the late 1950s. It has already achieved mass production, and after repeated development, it is not a "new" field. It seems that it is difficult to have "new". The second is that tungsten-based composite materials have been difficult to meet the development needs of cutting-edge technology. When Fan Jinglian chose this topic, the two words of the instructor moved Fan Jinglian, one sentence is "to make a thing that cannot be found in the information". One sentence is "you must not only be an academic leader in China in this field, but also a global academic leader."

"To make a thing that can't be found in the data" has become the goal of Fan Jinglian. After doing a lot of basic research, in 1998, Fan Jinglian dared to "hard bones" and took the lead in proposing the concept of "nano-composite" tungsten alloy ready-to-use nanotechnology. Fine-grained tungsten alloy, which is the first in China and abroad.

Prior to this, powder metallurgy preparation was like "cooking", which was prepared by mixing large particles of metal powder elements. Let the metal elements achieve atomic and molecular level in situ recombination, which was no different from "Arabian Nights". So "the resistance at the beginning is very big, because this is challenging the traditional method, many people are not optimistic.

After repeated failures and again, the breakthrough was finally found. The powder super-saturated solid solution caused the W-Ni-Fe powder to undergo a low-temperature melting characteristic transformation, and when sintered at 1350 to 1450 degrees Celsius, it can reach a density of more than 99%.

Tungsten and copper have large differences in melting point and are called two-phase pseudoalloys. Through nanocomposite, the mutual characteristics are changed, and the two metals which are not mutually melted are uniformly distributed at the atomic level, thereby changing the "false alloy" into "true alloy".

The idea is confirmed, and the research follows up. The related materials and components designed and developed according to this technology have been successfully applied to China's major strategic missiles. In 2015, Prof. Fan Jinglian and Zhuzhou Cemented Carbide Group Co., Ltd. jointly completed the “High Performance Tungsten Composites and Applications” project and won the second prize of National Technology Invention.

At that time, a new type of ultra-high-speed aircraft developed by the state, which was flying in the near-field for 5 to 20 hours, had a high temperature of 2000 to 3000 degrees Celsius on the surface of key structural components at the front end, and was subjected to strong surface oxidation and high dynamic pressure and high overload shock. This puts extremely demanding use requirements on the hot end member and is the most recognized technical problem recognized internationally.

Once, a report on hybrid rice allowed Fan Jinglian to shine. If ultra-high temperature ceramic materials and refractory metals were used to achieve “micro-nano-composite”, could it be complementary to hybrid rice, which has high ceramics. What are the properties of melting point, low density, and metal ductility?

"Hybrid" ceramic materials and refractory metals like hybrid rice are Fan Jinglian's new peak in the field of refractory metals. Compared with "metal + metal" composite materials, the difficulty of "metal + ceramic" forming composite materials increases geometrically, because one is organic material, one is inorganic material; one is conductive and heat conduction, one is non-conductive and heat conduction; one is extensible One is not malleable, and there is no basis for "composite" at all.

However, Fan Jinglian walked out of her own path. After several layers of experiments, her team finally developed an ultra-high temperature resistant composite material with a high-temperature strength of more than 5 times and a density reduction of half. This micro-nano composite lightweight refractory metal base The composite material realizes the high temperature toughness, light weight and anti-ablative design of refractory metal. Its high temperature strength is more than 5 times higher than the existing ultra-high temperature refractory metal, and the density is reduced by 1/2; it is repeatedly evaluated by wind tunnel and engine. The material has no damage and near zero ablation, which can achieve long-term anti-ablative, anti-scouring and anti-high-load shock in the ultra-high temperature environment of the air. It is quickly promoted in the ultra-high temperature field such as hypersonic weapon thermal protection and new high-energy engine. application.

At present, Professor Fan Jinglian has obtained nearly 50 invention patents. Following the selection of “Changjiang Scholars”, “National Outstanding Youth” and experts enjoying government subsidies from the State Council, in 2017, Fan Jinglian became the first winner of the National Innovation Award and won the He Liang He Li Technology Progress Award.

“In order to truly reflect its value, the research results can be truly applied.” In 2014, Fan Jinglian established a group of doctors, masters and engineers who have been engaged in research on new materials to create Changsha Micro-Nankun New Materials Co., Ltd. At present, Wei Na Kun has become the sole supplier of many types of products in the fields of aerospace, defense and military, and weapons and ships in China.

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