Ti-6Al-4V合金添加对原位合金化增材制造15-5PH不锈钢显微组织与力学性能的影响

Effect of Ti-6Al-4V Alloy Addition on the Microstructure and Mechanical Properties of 15-5PH Stainless Steel Prepared by In Situ Alloying Additive Manufacturing

研究了不同Ti-6Al-4V合金粉末添加对原位合金化增材制造15-5PH不锈钢显微组织和力学性能的影响,结合金相及背散射电子衍射显微组织、X射线衍射、扫描电镜断口及拉伸实验分析了原位合金化增材制造15-5PH不锈钢的晶粒细化机制及强韧化机理。结果表明:Ti-6Al-4V原位合金化后15-5PH不锈钢组织发生了等轴转变,显著细化晶粒的同时降低了织构强度,同时通过抑制马氏体相变使位错密度降低。15-5PH+0.8%Ti-6Al-4V和15-5PH+1.6%Ti-6Al-4V合金的屈服强度分别达1069 MPa和1021 MPa,远高于15-5PH不锈钢(680 MPa),且合金的延伸率明显提升,其较高的屈服强度和延伸率主要源于晶粒细化及内部位错密度的降低。

The effects of different Ti-6Al-4V alloy powder additions on the microstructure and mechanical properties of 15-5PH stainless steel prepared by in situ alloying additive manufacturing were investigated.The grain refinement and toughness mechanisms were analyzed by optical microscope,electron back scatter diffraction,X-ray diffraction,scanning electron microscope fracture analysis and tensile experiments.The results show that the microstructure of 15-5PH stainless steel changed after in situ alloying with Ti-6Al-4V alloy,which significantly refines the grain size while reducing the texture strength.And the dislocation density is reduced by inhibiting the martensite phase transition.The yield strengths of 15-5PH+0.8%Ti-6Al-4V and 15-5PH+1.6%Ti-6Al-4V alloy reached 1069 MPa and 1021 MPa respectively,which are much higher than those of 15-5 PH stainless steel(680 MPa).Meanwhile,the elongation of the in situ alloying alloys increases significantly.The higher yield strength and elongation are mainly due to grain refinement and the decrease in dislocation density.