铜合金化轻质钢屈服强度及氢脆性能的研究进展

Progress on yield strength and hydrogen embrittlement of Cu alloyed lightweight steel

随着全球能源危机及环境恶化的加剧,汽车行业在以高安全性为基础的前提下逐步推进汽车轻量化的发展模式,以实现低能耗低污染的目标。汽车所用材料中,钢铁材料约占整车质量的70%,因此,研发高性能的汽车用轻质钢迫在眉睫。目前,Fe-Mn-Al-C轻质钢,尤其是奥氏体基双相轻质钢和奥氏体轻质钢,凭借良好的综合性能及显著的减重效果成为发展潜力较强的汽车用钢,但是其同其他高强钢一样也面临屈服强度和抗氢脆断裂性能需要进一步提升的问题。基于此,聚焦国内外的相关研究现状发现添加铜元素是改善上述问题比较理想的合金化思路之一,钢中添加铜元素且配以合理的热处理工艺,可以实现晶粒内细小富铜颗粒和细小κ-碳化物颗粒的共同析出,且富铜颗粒的析出可以促进κ-碳化物颗粒的析出,充分利用各个析出相的特点达到提高轻质钢综合性能的目的。总结了铜元素对Fe-Mn-Al-C轻质钢屈服强度和氢脆性能的影响及作用机理,针对研究现状提出以下亟需解决的问题,即富铜颗粒和κ-碳化物颗粒共同析出的交互作用规律和耦合机制及其对钢变形行为的作用机制;富铜相和κ-碳化物的氢陷阱结合能及其对氢俘获位点及氢扩散速率的影响;富铜析出相的晶格转变类型及其与热处理工艺参数之间的关系。对进一步提高Fe-Mn-Al-C轻质钢的综合性能及促进其早日实现工业化生产应用具有一定的参考价值。

With the aggravation of global energy crisis and environmental degradation,the automotive industry has gradually promoted the development mode of vehicle lightweight on the premise of high safety to achieve the goal of low energy consumption and low pollution.Due to the fact that steel materials account for approximately 70%of the total weight of automobiles.Therefore,it is urgent to develop lightweight steel with excellent properties for automobiles.Currently,Fe-Mn-Al-C lightweight steel,especially austenitic dual phase lightweight steel and austenitic lightweight steel,has become a promising automotive steel due to its excellent comprehensive properties and significant weight reduction.However,like other high-strength steels,the yield strength and hydrogen embrittlement resistance of this steel need to be improved.Focusing on the current research status,it is found that adding Cu element is one of the ideal alloying ideas to improve the above issues.Adding Cu element to steel and reasonable heat treatment process can achieve the co-precipitation of fine Cu-rich particles and fineκ-particles within the grains,and the precipitation of Cu-rich particles can promote the precipitation ofκ-particles,which fully utilizes the characteristics of each precipitation phase to improve the comprehensive properties of lightweight steel.The effect and mechanism of Cu on the yield strength and hydrogen embrittlement properties of Fe-Mn-Al-C lightweight steel have been summerized.The following urgent issues need to be addressed in response to the current research status.The interaction law and coupling mechanism of the co-precipitation of Cu-rich particles andκ-carbide particles,as well as their impact on the deformation behavior of steel.The hydrogen trap binding energy of Cu-rich particles andκ-carbides particles and its influence on hydrogen capture sites and hydrogen diffusion rate.The lattice transformation of Cu-rich particles and their relationship with heat treatment process.It will have certain reference value for further improving the comprehensive properties of Fe-Mn-Al-C lightweight steel and promoting its industrial production and application as soon as possible.