Artificial Intelligence refers to a general field, which deals with creating machines capable of performing tasks that require human intelligence, such as problem-solving, reasoning, and perception.
Machine learning is the subfield of Artificial Intelligence, in which machines learn from data and improve their performance based on that learning, and no explicit programming may exist.
AI includes many technologies that encompass robotics, natural language processing, and computer vision, whereas ML refers to exposing training algorithms to data in order to look for patterns or in order to make predictions. In other words, all machine learning is AI, but not vice versa.