Mechanical Properties and Fracture Mechanism of Selective Laser Melting Manufactured Nickel-Based Alloy by Small Punch Test Over a Wide Temperature Range.

The high-temperature mechanical properties and fracture mechanism of selective laser melting (SLM) manufactured nickel-based alloy are highly important for its application. In this article, small punch test (SPT) method is used to study the mechanical properties of SLM-manufactured GH4169 over a wide temperature range from 25°C to 600°C. With the increase of temperature, the decreasing ratio of maximum load is only 18.75% from 25°C to 600°C, and the yield load fluctuates with temperature, proving that it maintains the excellent load-bearing ability at high temperature. From the variation law of the normalized SPT fracture energy versus temperature, the ductile-to-brittle transition temperature of SLM-manufactured GH4169 is 413.63°C indicating the change of fracture mechanism. Moreover, the "fish scale" printed layer near the fracture surface changes from the difficult deformed microstructure to significant deformed one, leading to the variation of the fracture mechanism from brittle cleavage fracture traversing the printed layers to ductile fracture along the printed layers. This article reveals the variations of strength parameters, fracture energy, and fracture mechanism with temperature for SLM-manufactured GH4169 over a wide temperature range, which provides basic data for its application at different temperatures.