Parvez Mohammad Masud, Pan Tan, Chen Yitao, Karnati Sreekar, Newkirk Joseph W, Liou Frank
Department of Mechanical and Aerospace Engineering, Missouri University of Science and Technology, Rolla, MO 65401, USA.
Material Science and Engineering, Missouri University of Science and Technology, Rolla, MO 65401, USA.
Materials (Basel). 2020 Mar 31;13(7):1591. doi: 10.3390/ma13071591.
In additive manufacturing, the variation of the fabrication process parameters influences the mechanical properties of a material such as tensile strength, impact toughness, hardness, fatigue strength, and so forth, but fatigue testing of metals fabricated with all different sets of process parameters is a very expensive and time-consuming process. Therefore, the nominal process parameters by means of minimum energy input were first identified for a dense part and then the optimized process parameters were determined based on the tensile and impact toughness test results obtained for 304L stainless steel deposited in laser powder bed fusion (LPBF) process. Later, the high cycle fatigue performance was investigated for the material built with these two sets of parameters at horizontal, vertical, and inclined orientation. In this paper, displacement controlled fully reversed (R = -1) bending type fatigue tests at different levels of displacement amplitude were performed on Krouse type miniature specimens. The test results were compared and analyzed by applying the control signal monitoring (CSM) method. The analysis shows that specimen built-in horizontal direction for optimized parameters demonstrates the highest fatigue strength while the vertical specimen built with nominal parameters exhibits the lowest strength.
在增材制造中，制造工艺参数的变化会影响材料的力学性能，如拉伸强度、冲击韧性、硬度、疲劳强度等，但对采用所有不同工艺参数集制造的金属进行疲劳测试是一个非常昂贵且耗时的过程。因此，首先针对一个致密部件确定了基于最小能量输入的名义工艺参数，然后根据在激光粉末床熔融（LPBF）工艺中沉积的304L不锈钢的拉伸和冲击韧性测试结果确定了优化工艺参数。随后，研究了用这两组参数在水平、垂直和倾斜方向构建的材料的高周疲劳性能。在本文中，对克劳斯型微型试样进行了不同位移幅值水平下的位移控制完全反向（R = -1）弯曲型疲劳试验。通过应用控制信号监测（CSM）方法对测试结果进行了比较和分析。分析表明，采用优化参数在水平方向构建的试样表现出最高的疲劳强度，而采用名义参数构建的垂直试样表现出最低的强度。
