以即時性中子繞射量測不同積層方向製造的不鏽鋼性質

Abstract

近年來積層製造技術蓬勃發展，在工程上以選擇性雷射融化技術(SLM, Selective laser melting)為主，進行金屬粉末材料的成品印製。過程中金屬粉末會一層一層的鋪成且融化，物件便會呈現層狀結構。層狀結構的層數以及因印製造成的缺陷排列便會影響材料的性質，如機械性質、微結構等。本實驗研究兩種不同積層方向製造的不鏽鋼樣品，其一為積層方向平行拉伸方向，製作成圓棒樣品，其二為積層方向垂直於拉伸方向，製作成平板樣品，將兩種樣品在室溫下進行單軸拉伸測試，並使用即時性中子量測獲得即時性的晶格資訊。此外，利用繞射峰擬合軟體MAUD (Material Analysis Using Diffraction)以及CMWP (Convolutional Multiple Whole Profile)來取得材料晶格結構、相比例分析、微結構資訊等，與顯微技術觀測影像作為印證。藉由上述獲得的資訊了解積層方向不同對材料造成的影響，進而去描述積層過程的樣品製造策略。

The field of additive manufacturing (AM) has experienced significant growth around all worlds. In engineering, selective laser melting (SLM) is an additive manufacturing process for building metallic parts. Metallic parts are created layer by layer to form a layered structure. The mechanical properties of metallic parts are attributed to the numbers of building layers and the orientation of defects which is relative to building direction. In this research, we prepared two types of samples made of PH15-5 stainless steel fabricated by two different building direction. One building direction is parallel to loading direction, called cylindrical sample, and the other building direction is perpendicular to loading direction. During the tensile test, we apply in-situ neutron diffraction measurements with two orthogonal detectors to resolve the differences from additive directions. Besides, we used rietveld software, MAUD and CMWP to understand the crystal structure, phase evolution and microstructures of this material. When we know the information about the difference properties between samples fabricated by two different building directions, the strategy of additive manufacturing can be described clearly.