Seely D, Bagheri M A, Dickel D, Cho H E, Rhee H, Horstemeyer M F
Haynes International, Kokomo, IN 46904, USA.
Department of Mechanical Engineering, Mississippi State University, Starkville, MS 39762, USA.
Materials (Basel). 2024 Jul 14;17(14):3491. doi: 10.3390/ma17143491.
We quantify the chemistry-process-structure-property relationships of a Ti-6Al-4V alloy in which titanium-boron alloy (Ti-B) was added in a functionally graded assembly through a laser-engineered net shaping (LENS) process. The material gradient was made by pre-alloyed powder additions to form an in situ melt of the prescribed alloy concentration. The complex heterogeneous structures arising from the LENS thermal history are completely discussed for the first time, and we introduce a new term called "Borlite", a eutectic structure containing orthorhombic titanium monoboride (TiB) and titanium. The β-titanium grain size decreased nonlinearly until reaching the minimum when the boron weight fraction reached 0.25%. Similarly, the transformed α-titanium grain size decreased nonlinearly until reaching the minimum level, but the grain size was approximately 2 μm when the boron weight fraction reached 0.6%. Alternatively, the α-titanium grain size increased nonlinearly from 1 to 5 μm as a function of the aluminum concentration increasing from 0% to 6% aluminum by weight and vanadium increasing from 0% to 4% by weight. Finally, the cause-effect relationships related to the creation of unwanted porosity were quantified, which helps in further developing additively manufactured metal alloys.
我们对一种Ti-6Al-4V合金的化学-工艺-结构-性能关系进行了量化，该合金通过激光工程净成形（LENS）工艺在功能梯度组件中添加了钛硼合金（Ti-B）。材料梯度是通过添加预合金粉末形成规定合金浓度的原位熔体来实现的。首次全面讨论了由LENS热历史产生的复杂非均匀结构，并且我们引入了一个新术语“硼化物”，它是一种包含正交晶系一硼化钛（TiB）和钛的共晶结构。当硼的重量分数达到0.25%时，β钛晶粒尺寸呈非线性减小直至达到最小值。同样，转变后的α钛晶粒尺寸也呈非线性减小直至达到最小水平，但当硼的重量分数达到0.6%时，晶粒尺寸约为2μm。另外，随着铝的重量浓度从0%增加到6%以及钒的重量浓度从0%增加到4%，α钛晶粒尺寸从1μm到5μm呈非线性增加。最后，对与产生有害孔隙率相关的因果关系进行了量化，这有助于进一步开发增材制造的金属合金。
