热处理制度对大直径钛合金管材组织与性能的影响

摘要

采用4种热处理制度对TC4E LI钛合金大直径管材试样进行处理,研究不同热处理制度对其组织与性能的影响.结果表明:经750℃×1 h/AC普通退火处理后,组织为魏氏组织,具有较高的冲击韧性和断裂韧性,强度较低;经900℃×1 h/AC处理后,组织为晶界模糊的魏氏组织,同样具有较高的冲击韧性和断裂韧性,且强度较普通退火有所上升;经930℃×1 h/WQ+580℃×6 h/AC处理后,组织为魏氏组织,a片层较为细小,其断裂韧性(96.8 MPa-m1/2)、强度(892 MPa)、断面收缩率(42％)以及伸长率(16.0％)达到4种处理制度下的最大值,但冲击韧性急剧下降;经930℃×l h/WQ+650℃×6 h/AC处理后,组织为魏氏组织,晶内α相片层取向呈编织状,具有较高的强度和断裂韧性,冲击韧性较差.%Four kinds of heat treatment processes were used to study the effect on the microstructure and properties of the TC4ELI big-diameter titanium alloy tubes.The results show that after the processing of 750 ℃ × 1 h/AC,the widmanstatten structure is acquired,the impact toughness and fracture toughness are much higher,but the tensile strength is the lowest;after the processing of 900 ℃ × 1 h/AC,the widmanstatten structure with fuzzy grain boundary is obtained,the impact toughness and fracture toughness are as high as that of the previous processing,and the tensile strength is increased;after the processing of 930 ℃ ×1 h/WQ+580 ℃ ×6 h/AC,the widmanstatten structure with very fine α lamellas is obtained,the fracture toughness(96.8 MPa · m1/2),tensile strength(892 MPa),reduction in area(42％) and elongation(16.0％) are the highest among the properties after four kinds of heat treatment processes,while the impact toughness is decreased seriously;after the processing of 930 ℃ × 1 h/WQ+650 ℃ ×6 h1AC,the widmanstatten structure with α phase lamellas interwovened is acquired,the tensile strength and fracture toughness are also higher,but the impact toughness is the lowest value.