Experimental investigation on properties of laminates produced by Large Strain Extrusion Machining

Abstract

Efficient manufacturing practices aim to minimize energy consumption and waste generation, promoting sustainability. This study focuses on fabricating titanium alloy laminates using the Large Strain Extrusion Machining (LSEM) process. Unlike conventional methods, LSEM allows for single-pass production of laminates with controlled microstructures. This approach contrasts with traditional rolling methods, which are complex for high-strength materials like titanium alloys due to the need for multiple stages and challenges in texture control. By employing LSEM, we aim to streamline production processes while ensuring precise microstructural control in a continuous operation, particularly beneficial for aerospace applications. An experimental test rig was fabricated and utilized alongside a lathe machine to facilitate the constrained production of laminates. In this study, three distinct materials were chosen: commercially pure titanium, Ti-6Al-4V, and Ti-6Al-7Nb, each intended for laminate fabrication with varying strain rates. Four different levels of strain rates, ranging between 0.25 s-1 to 2 s-1, were employed to produce four laminate samples for each material. Following production, the laminates underwent comprehensive mechanical and metallurgical characterization, including micro and nano hardness testing, surface roughness analysis, measurement of average crystallite size, and evaluation of microstrain. The results of each characterization parameters are presented and compared with it based own raw material of all the three selected materials. Overall, it is found from the study that the properties were improved from the bulk material i.e. commercially pure titanium, Ti-6Al-4V, and Ti-6Al-7Nb. Microhardness assessments of both the titanium alloy bulk materials and laminates consistently showed higher hardness values in the laminates compared to the parent materials. Specifically, the laminates exhibited improvements in microhardness (HV) ranging from 25% to 52% higher than CP Ti, 7% to 25% higher than Ti-6Al-4