温度对铁基材料共渗层组织结构及性能的影响

Effect of temperature on microstructure and properties of co-infiltrated layer of iron-based materials

采用包覆渗硼法对铁基材料共渗强化固体颗粒,在800、900、1000℃下保温3、5、7 h。用HT-1000摩擦磨损试验机在室温下对经硼化处理和未处理的铁基材料进行摩擦磨损试验。结果表明:在800℃和900℃共渗层的主要物相为Fe2B,升温至1000℃,试样表层形成少且薄的FeB,随着温度的升高和保温时间延长,共渗层厚度增加,但存在最佳保温温度与时间,此时共渗层较厚、组织致密,继续升温厚度增加相对缓慢且组织、性能不佳;未渗硼试样磨损机制表现为严重塑性变形和表面软化,渗硼试样磨损机制为表面层裂纹形成和剥落,即分层磨损机制。经900℃,5 h渗硼试样摩擦表面层只有微裂纹相对比较完整,耐磨性较好。

The iron-based material was subjected to solid particle co-infiltration strengthening by coating boronizing method. The process was carried out at 800,900 and 1 000 ℃,respectively,holding for 3,5 and 7 h,followed by the friction and wear test at room temperature on the boronized and untreated iron-based material with the HT-1000 friction and wear test machine. The results show that the main phase of the co-infiltrated layer at 800 ℃ and 900 ℃ is Fe2 B. When heating to 1 000 ℃,little and thin FeB forms on the surface layer of the sample. With the increase of the holding temperature and the holding time,the thickness of the co-infiltrated layer increases,but there are optimal holding temperature and holding time. In this optimal state,the coinfiltrated layer with bigger thickness and dense structure can be obtained. With increasing temperature,the thickness increases relatively slowly and the structure and performance become poor. The wear mechanism of the sample without boronizing is severe plastic deformation and surface softening,while the wear mechanism of the sample after boronizing treatment is delamination wear mechanism. The sample treated after 5 h boronizing at 900 ℃ is relatively complete and wear-resistant with only microcracks on the surface layer.