摘要
采用不同转速对3 mm厚Q235低碳钢进行搅拌摩擦加工,对比分析了加工区的微观组织和力学性能。结果表明：在475 r/min较低转速时,组织演变以铁素体动态再结晶为主,形成细小的铁素体组织。在750 r/min较高转速时,加工伴随相变过程的发生,形成铁素体、马氏体及铁素体和碳化物混合体的复合组织,且显微硬度和抗拉强度分别比母材提高了25.4%和35.3%,而搅拌摩擦加工后力学性能的显著提高,主要归结于细晶强化、弥散强化和位错强化。加工前后试样均呈现微孔聚合韧性断裂特征。
Low carbon steel Q235 with thickness of 3 mm was friction-stir processed via different rotational rates, and the microstrucmre,mechanical properties were investigated. The results indicate that at the lower rotation rate of 475 r/rain, the microstrueture evolves mainlyvia ferrite dynamic recrystallization to form a fine ferrite structure. With the rotation rate increases to 750 r/rain, the phase transformationduring FSP the friction-stir process finally resulted to a complex microstmcture consisting of ferrite, martensite, and the mixture of teri＇ite audcarbide in the stir zone. The microhardness and ultimate tensile strength were 25.4% and 35.3% higher than those of the BM, respec＇tively.The enhancement of mechanical properties by friction stir processing may be caused mainly by grain refinement strengthening, dispersionstrengthening and dislocation strengthening. Both the fracture surfaces before and ＂,：ffter friction stir processing exhibit dimple ductile fracturecharacterization.
出处
《金属热处理》
CAS
CSCD
北大核心
2018年第2期80-85,共6页
Heat Treatment of Metals
基金
国家自然科学基金联合基金(U1360105)
关键词
Q235低碳钢
搅拌摩擦加工
微观组织
力学性能
Q235 low carbon steel
friction stir processing
microstructure
mechanical properties
