There is no sword called "Xuanyuan Sword" in real history, and the technology of smelting copper in the era of the Yellow Emperor was very low, let alone smelting iron. But in the historical records, it is indeed recorded that the Yellow Emperor had a sword. The Classic of Mountains and Seas and the Second Classic of Zhongshan say that "Kunwu Mountain is full of red copper."
And in Wang Jia's "Notes", it is recorded that "Kunwu Mountain is full of red gold and the color is like fire. Yesterday, the Yellow Emperor killed Chiyou, and Chen Bing was here. Digging a hundred feet deep is not as deep as a spring, and it is like a star. Diduo Dan, the stone is copper, and the copper color is green. " However, it didn't mention the name of the sword.
Legend of the Famous Sword quotes A Journey to the Yellow Emperor, which records that "Xuanyuan took the copper from the first mountain, cast a sword and carved ancient Chinese characters." However, there is no such passage in A Journey to the Yellow Emperor. So it should be invented by later generations.