摘要
采用同轴送粉的沉积方式进行了3D打印TC4钛合金的研究,分析了激光功率、扫描速度、扫描方向以及固溶时效热处理工艺对TC4钛合金组织和力学性能的影响,并分析了其作用机理。结果表明:不同激光功率下TC4钛合金的宏观组织都为定向外延生长的粗大β柱状晶形态;当扫描速度从0.12 m/min增加至0.60 m/min时,柱状晶的宽度呈现逐渐减小的趋势,而柱状晶高度逐渐增加,且随着扫描速度的增加,柱状晶与扫描方向的夹角逐渐增大;单向扫描时TC4钛合金的柱状晶呈现定向外延生长趋势,而往返扫描时TC4钛合金的柱状晶由定向生长转变为双相生长,且沉积层间还出现了一定数量的等轴晶。3D打印TC4钛合金的强度都超过国标对铸件和锻件退火态TC4钛合金的要求,但是断后伸长率较低;经过固溶和时效热处理后,TC4钛合金的强度略有降低而断后伸长率明显提高,主要原因与沉积态魏氏组织转变为热处理态网篮组织有关。
3D printing of TC4 titanium alloy by coaxial powder feeding was studied, the effect of laser power, scanning speed, scanning direction and solution aging treatment on microstructure and mechanical properties of TC4 titanium alloy was analyzed, and its mechanism was analyzed. The results show that, the microstructure of the TC4 titanium alloy under different laser power is the shape of the thick beta columnar crystal grown by directional epitaxy; when the scanning speed is increased from 0.12 m/min to 0.60 m/min, the width of columnar crystal decreases gradually, but the columnar height increases gradually, and with the increase of scanning speed, the angle between the columnar crystal and scanning direction increases gradually; columnar crystal of TC4 titanium alloy shows the orientation of the epitaxial growth trend during unidirectional scanning, however, the columnar crystals of TC4 titanium alloy changes from directional growth to double phase growth when round scanning, and a certain number of equiaxed grains are formed between the layers. The strength of3 D printing titanium alloy exceeds the national standard of casting and forging-annealed TC4 titanium alloy, but the elongation is lower; after solid solution and aging heat treatment, the strength of TC4 alloy decreases slightly and the elongation increases significantly, which are main due to the microstructure tansforming from deposited widmanstatten structure to heat-treated basket structure.
出处
《热加工工艺》
CSCD
北大核心
2017年第16期220-224,共5页
Hot Working Technology
关键词
3D打印
TC4钛合金
成形
热处理
性能
3D printing
TC4 titanium alloy
forming
heat treatment
performance
