Research On Forming Defects Of Laser Selective Melting Of Alumina And Their Suppression Methods

Selective Laser Melting(SLM)ceramic technology is developing rapidly,and it's shape-independent characteristic makes it possible to form complex-shaped ceramic components,but ceramics materials,especially alumina,have high melting point,low laser energy absorption.high brittleness and poor toughness,which makes it easy for SLM alumina components to produce various internal defects under the high temperature gradient and large laser shock caused by high-energy laser,and eventually damages the processability and mechanical properties of SLM alumina parts seriously.Facing the processing difficulties and poor properties,it is urgent to study the internal defects theory of SLM alumina and propose defect suppression methods based on the principle of defect generation and expansion.In order to establish the defects theory and design defect suppression methods of SLM alumina based on the research status worldwild,the alumina SLM experiment was designed under different laser process parameters and scanning strategies to provide an analytical basis for internal defect research,then the main types,forming and expansion mechanism and performance failure mode of SLM alumina internal defects were systematically analyzed.Various defect suppression methods were designed from the perspective of optimizing process parameters,adjusting material system and high temperature heat treatment,and the principle,effect and laser influence of defect suppression are elaborated.At last,the fiber-reinforced SLM alumina matrixes were designed to suppress cracks particularly,and the selection,surface treatment,layout and suitable laser parameters for fibers-reinforce were explored to analyze the effect of toughening the matrix and inhibiting cracks.