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利用混粉准干式电火花表面强化技术对TC4钛合金进行表面强化。工作介质中混入B4C粉末,工具电极选用石墨电极,在其表面形成富含C、B、Ti、Al等元素的强化层来改善钛合金表面的硬度。结果表明,强化后合金表面形成一层致密的、呈菊花瓣状层叠式组织的强化层,与基体结合良好,电流增大菊花瓣状晶粒明显增大;经峰值电流为3.7和6.6A的电火花强化后,强化层硬度(HV)由强化处理前的312分别提高至899和1 039。XRD分析表明,强化层中出现了TiC、TiB、B_8C、Al_3BC、Al_3Ti和Al_5Ti_2等相,电流增大至6.6A时还出现了Al_(3.3)Ti亚稳相,且Ti-Al化合物相含量明显增多,实现了对钛合金表面的混杂强化。
TC4 titanium alloy is surface strengthened by quasi-dry electric spark surface strengthening technology. B4C powder is mixed into the working medium, graphite electrode is used as the electrode of the tool, and the surface of the tool electrode is reinforced with elements such as C, B, Ti and Al to improve the hardness of the titanium alloy surface. The results show that a dense layer of chrysanthemum-lamellar laminated structure is formed on the surface of the alloy after strengthening, which has a good combination with the substrate and the current-increasing chrysanthemum petal grains increase obviously. After the peak current is 3.7 and 6.6A After the spark enhancement, the hardness (HV) of the strengthened layer increased from 312 before strengthening to 899 and 1039 respectively. XRD analysis showed that TiC, TiB, B_8C, Al_3BC, Al_3Ti and Al_5Ti_2 phases appeared in the strengthening layer, Al_ (3.3) Ti metastable phase appeared when the current increased to 6.6A, and the phase content of Ti-Al compound was obvious Increased, to achieve the hybrid surface hardening of titanium.