Effects of microstructure and inherent stress on residual stress induced during powder bed fusion with roller burnishing
Effects of microstructure and inherent stress on residual stress induced during powder bed fusion with roller burnishing
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DOI：
10.1016/j.ijmecsci.2022.107092
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发表时间：
2022-02-09
影响因子：
7.3
通讯作者：
Malik, Arif
中科院分区：
文献类型：
--
作者：
Sunny, Sumair;Mathews, Ritin;Malik, Arif
一种混合金属增材制造（AM）工艺，结合激光粉末床融合（PBF-LB）与层间抛光的研究使用一个全面的建模框架，提供新的见解如何从激光粉末床融合过程中的不均匀的微观结构和残余应力影响诱导的残余应力场，在层间抛光过程中演变。研究人员最近研究了由类似的混合金属添加剂工艺引起的微观结构的变化，然而，仅假设所得的微观结构对诱导的残余应力有一些影响。此外，研究人员已经数值研究了抛光/轧制工艺参数对诱导应力的影响，但忽略了微观结构的影响，从而做出均匀、各向同性的假设。这种做法抑制了预测的微观结构驱动的各向异性，可以存在于不均匀的熔融层。本文参数化检查的微观结构建模，固有的残余应力映射，和环境温度的混合金属添加剂过程中诱导的残余应力的影响。演示的建模框架结合了固有的残余应力，出现从激光粉末床融合过程中，以及预测的微观结构，在随后的抛光模拟，以阐明其个人和综合的影响，抛光引起的残余应力。研究结果表明，建模一个不均匀的PBF-LB微观结构引入了各向异性分布的塑性应变和残余应力沿着抛光表面;周期性的平面应力分量沿着处理过的表面相一致的PBF-LB扫描线。固有残余应力对抛光引起的残余应力的影响不太显著，但仍然是可观察的。升高的温度不仅降低了引起的压缩残余应力的大小，而且还导致沿着扫描线和舱口空间预测的残余应力分量大小的较小变化。所提出的框架提供了新的见解解耦的影响，微观结构和PBF-LB残余应力的抛光引起的应力是无法区分通过实验技术。然而，平均残余应力通过深度的试样，以及抛光后的表面硬度大小的趋势显示良好的协议，分别与X射线衍射和显微压痕测量文献中记载的。
A hybrid metal-additive manufacturing (AM) process that combines laser-based powder bed fusion (PBF-LB) with interlayer burnishing is investigated using a comprehensive modeling framework to provide new insights into how the inhomogeneous microstructure and residual stress from the laser powder bed fusion process affect the induced residual stress field that evolves during interlayer burnishing. Researchers have recently studied changes in microstructure resulting from similar hybrid metal-additive processes, however, it was only hypothesized that the resulting microstructure has some influence on the induced residual stress. In addition, researchers have numerically investigated the influence of burnishing/rolling process parameters on induced stress but neglected the effects of microstructure, thereby making homogeneous, isotropic assumptions. Such practice inhibits the prediction of microstructure-driven anisotropy that can exist in the inhomogeneous fused layer. This paper parametrically examines the influence of microstructure modeling, inherent residual stress mapping, and environment temperature on the induced residual stress during the hybrid metal-additive process. The demonstrated modeling framework incorporates inherent residual stresses that emerge from the laser powder bed fusion process, as well as the predicted microstructure, in a subsequent burnishing simulation to elucidate their individual and combined influences on the burnishing-induced residual stress. Findings reveal that modeling an inhomogeneous PBF-LB microstructure introduces an anisotropic distribution of plastic strain and residual stress along the burnished surface; a periodicity in planar stress components along the treated surface coincides with the PBF-LB scan lines. Effects of inherent residual stress on the burnishing induced residual stress is less significant, but nonetheless observable. Elevated temperatures not only reduce the magnitude of compressive residual stress induced but also result in less variation of residual stress component magnitudes predicted along scan lines and hatch spaces. The presented framework offers new insights into the decoupled influences of microstructure and PBF-LB residual stress on burnishing-induced stresses that are not distinguishable via experimental techniques. However, trends in averaged residual stress through the depth of the specimen, as well as surface hardness magnitudes after burnishing show good agreements, respectively, with X-ray diffraction and microindentation measurements documented in the literature.