Arbogast Alexander, Roy Sougata, Nycz Andrzej, Noakes Mark W, Masuo Christopher, Babu Sudarsanam Suresh
Department of Mechanical, Aerospace and Biomedical Engineering, University of Tennessee, Knoxville, TN 37916, USA.
Manufacturing Science Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA.
Materials (Basel). 2020 Dec 12;13(24):5683. doi: 10.3390/ma13245683.
This work investigated the linear thermal expansion properties of a multi-material specimen fabricated with Invar M93 and A36 steel. A sequence of tests was performed to investigate the viability of additively manufactured Invar M93 for lowering the coefficient of thermal expansion (CTE) in multi-material part tooling. Invar beads were additively manufactured on a steel base plate using a fiber laser system, and samples were taken from the steel, Invar, and the interface between the two materials. The CTE of the samples was measured between 40 °C and 150 °C using a thermomechanical analyzer, and the elemental composition was studied with energy dispersive X-ray spectroscopy. The CTE of samples taken from the steel and the interface remained comparable to that of A36 steel; however, deviations between the thermal expansion values were prevalent due to element diffusion in and around the heat-affected zone. The CTEs measured from the Invar bead were lower than those from the other sections with the largest and smallest thermal expansion values being 10.40 μm/m-K and 2.09 μm/m-K. In each of the sections, the largest CTE was measured from samples taken from the end of the weld beads. An additional test was performed to measure the aggregate expansion of multi-material tools. Invar beads were welded on an A36 steel plate. The invar was machined, and the sample was heated in an oven from 40 °C and 160 °C. Strain gauges were placed on the surface of the part and were used to analyze how the combined thermal expansions of the invar and steel would affect the thermal expansion on the surface of a tool. There were small deviations between the expansion values measured by gauges placed in different orientations, and the elongation of the sample was greatest along the dimension containing a larger percentage of steel. On average, the expansion of the machined Invar surface was 42% less than the expansion of the steel surface. The results of this work demonstrate that additively manufactured Invar can be utilized to decrease the CTE for multi-material part tooling.
本研究调查了由因瓦合金M93和A36钢制成的多材料试样的线性热膨胀特性。进行了一系列测试，以研究增材制造的因瓦合金M93在降低多材料零件模具热膨胀系数（CTE）方面的可行性。使用光纤激光系统在钢基板上增材制造因瓦合金珠，从钢、因瓦合金以及两种材料之间的界面取样。使用热机械分析仪在40℃至150℃之间测量样品的CTE，并通过能量色散X射线光谱研究元素组成。从钢和界面处取样的样品的CTE与A36钢的CTE相当；然而，由于热影响区及其周围的元素扩散，热膨胀值之间存在偏差。从因瓦合金珠测得的CTE低于其他部分，最大和最小热膨胀值分别为10.40μm/m-K和2.09μm/m-K。在每个部分中，从焊缝末端取样的样品测得的CTE最大。进行了另一项测试，以测量多材料工具的总膨胀。在A36钢板上焊接因瓦合金珠。对因瓦合金进行加工，然后将样品在烤箱中从40℃加热到160℃。将应变片放置在零件表面，用于分析因瓦合金和钢的组合热膨胀如何影响工具表面的热膨胀。放置在不同方向的应变片测得的膨胀值之间存在小偏差，样品沿含钢比例较大的尺寸方向的伸长最大。平均而言，加工后的因瓦合金表面的膨胀比钢表面的膨胀小42%。本研究结果表明，增材制造的因瓦合金可用于降低多材料零件模具的CTE。
